Registration in Bulgaria’s Central Professional Register of Builders (CPRB) — Categories, Groups and Procedure (2026)

Legal Framework

• Construction Chamber Act (ZKS) — State Gazette No. 108/2006, last amended by State Gazette No. 25/2019. It sets out who must register, the general requirements, the deadlines and the grounds for removal.
• Rules on Entry in and Maintenance of the CPRB (the CPRB Rules) — State Gazette No. 100/2017, in force since 1 January 2018. They define the groups of works, the quantitative criteria for the first, second and third categories, the documents and the electronic procedures of the register.
• Spatial Planning Act (ZUT) — classifies construction works into categories (Art. 137(1)) and sets the financial penalties for builders working without registration (Art. 237(1), items 8–11).

Entry, refusal and removal are decided by the Commission for the Maintenance and Use of the CPRB (Arts. 26–27 ZKS), whose 15 members are elected by the Chamber’s general assembly. Membership of the Construction Chamber is voluntary (Art. 5 ZKS) and is not among the registration requirements of Art. 15 ZKS: CPRB registration and KSB membership are two different things.

Who Must Register in the CPRB — and Who Need Not

The ZKS applies to Bulgarian and foreign natural and legal persons registered as traders under their national law, their branches, and state and municipal enterprises that build in Bulgaria (Art. 3(1) ZKS). Registration is mandatory for builders performing:

• construction works of categories one to five under Art. 137(1) ZUT, or
• individual types of construction and installation works listed under “Construction” in the Classification of Economic Activities (Art. 3(2) ZKS).

Consortia. Where several persons join forces for a project, at least one participant must be registered; the others do not acquire a right to build on their own (Art. 3(3)–(4) ZKS).

Exemptions. Low-rise residential and holiday buildings, and works under Art. 137(1)(5)(c) and (d) ZUT with a gross built-up area of up to 100 m², may be built by unregistered builders (Art. 14(2) ZKS). The sixth category is not among the categories for which the CPRB registers builders.

The client is bound too: the construction site may be opened and the site order book certified only after the client presents a contract with a CPRB-registered builder, except for the works under Art. 14(2) ZKS (Art. 157(2) ZUT).

Construction Categories under Art. 137 ZUT

The category reflects the characteristics, significance, complexity and operational risks of the works. A project that falls into two categories by different criteria is placed in the higher one (Art. 137(4) ZUT). Examples from the Act:

A builder registered for the first category may carry out works of all categories; one registered for the second, all except the first; one registered for the third, fourth and fifth, only those (Art. 14(3)–(5) ZKS). The right applies within the group for which the builder is registered (Art. 9(7) of the CPRB Rules).

Groups of Works and Individual Construction Works

In addition to the category, the builder registers in one or more groups (Art. 5(1) of the CPRB Rules):

• Group 1 — building construction (residential, public-service, industrial), related infrastructure, electronic communications networks and facilities.
• Group 2 — transport infrastructure.
• Group 3 — energy infrastructure.
• Group 4 — public-works infrastructure, hydraulic engineering and environmental protection (this is where water supply and sewerage belong).
• Group 5 — individual construction and installation works — a separate group subdivided by the “Construction” section of the Classification of Economic Activities (Arts. 6 and 14(2) of the CPRB Rules). The Rules refer to KID-2008; KSB has published a correspondence table to KID-2025.

Within each of groups 1–4 registration is by sub-group: categories one to five, two to five, three to five, or four and five (Art. 5(4)). The certificate states the group and sub-group (Art. 14(1)). For example, a newly formed residential builder may start in Group 1, sub-group “fourth and fifth category”, and extend its scope once it meets the third-category criteria.

Registration Requirements

General requirements for all categories (Art. 15(1) ZKS)

• No overdue public tax or social security liabilities (unless rescheduled or deferred); the Commission checks this with the National Revenue Agency ex officio.
• The builder is not declared insolvent and is not in insolvency or liquidation proceedings.
• Technical equipment for the works applied for — owned or hired; hired equipment is shown by a framework or leasing contract.
• Staff employed under employment contracts for technical management, quality control and occupational health and safety (at least one person for each of the three functions under the Commission’s instructions). A civil (service) contract does not satisfy this requirement.
• Technically qualified staff: civil engineers, engineers, architects, or persons with four-year secondary education in “Architecture and Construction” or “Technology” (Art. 163a(2) ZUT).
• Workers with the required vocational qualifications.
• Valid compulsory professional liability insurance of the builder (Art. 171 ZUT), matching the category applied for.

Works on immovable cultural heritage also require restoration experience and an architect on staff (Art. 15(4) ZKS).

Quantitative criteria by category (Art. 9(2)–(4) of the CPRB Rules)

The thresholds in the Rules are stated in leva; under Art. 11(2) of the Euro Introduction Act they apply in euro at the fixed rate of 1.95583. Financial data come from the annual financial statements for the previous year. When assessing experience, the Commission accepts, for the first and second categories, a project or phase completed within the last 5 years and evidenced by a building permit, a contract and an Act Form 15; for the third category, works within the last 5 years evidenced by a contract and a handover protocol (Decision No. 1147/2018).

Newly formed companies

A builder operating for less than three years provides the data on experience, training and finances for its last year only (Art. 16(4) ZKS). As the fourth and fifth categories carry no quantitative thresholds and no experience requirement, a new company can register in the sub-group “fourth and fifth category” if it has the staff on employment contracts, the equipment and the insurance. With zero revenue the entry price is the minimum — EUR 613.55 excluding VAT. If you still need to set up the company, see company registration in Bulgaria.

Documents for Initial Registration

The application is completed in the electronic system at register.ksb.bg. It is accompanied by (Art. 19(3) of the CPRB Rules):

1. diplomas evidencing the qualifications of the technical staff;
2. a National Revenue Agency statement of all current employment contracts;
3. a statement of staff numbers and qualifications by category;
4. proof of training of the person responsible for occupational health and safety;
5. a statement of staff training over the last three years;
6. a statement of machinery, plant and equipment;
7. licences and certificates for works involving high-risk equipment, where applicable;
8. a statement of works completed over the last three years, with supporting documents (building permit, contract, Act Form 15 or acceptance protocol);
9. financial information from the annual financial statements for the last three years;
10. documents on penalties imposed under ZUT (Art. 16(3)(11) ZKS);
11. a statement of insurance cover;
12. proof of payment of the entry price;
13. for immovable cultural heritage — a certificate under Art. 165 of the Cultural Heritage Act and an opinion of the National Institute for Immovable Cultural Heritage.

Tax and social security data are requested by the Commission ex officio (Art. 19(4)). For paper filings, copies are certified by the builder’s legal representative.

Registration and Annual Service Prices (2026)

These are not state fees but service prices set by the KSB general assembly (Art. 10(1)(4) ZKS; § 3 of the CPRB Rules). The current KSB price list, as at 2026:

Example: a builder registered in one group for the fourth and fifth categories pays 1.0 × EUR 186.62 = EUR 186.62 a year plus VAT; for the first category in one group, about EUR 503.87 plus VAT.

If the applicant does not meet the requirements of Art. 15 ZKS, 90% of the entry price is refunded. Payment is made by bank transfer to the KSB account before the application is filed (§ 3(2) of the CPRB Rules). KSB membership dues are not part of these prices.

Registration Procedure — Step by Step

1. System account. Create a user account at register.ksb.bg and complete the electronic application, ranking the groups by priority.
2. Payment of the entry price to the KSB account.
3. Filing — on paper at the regional “Register” unit at the builder’s seat (in person by the legal representative, by a proxy with a notarised power of attorney or by a lawyer with a lawyer’s power of attorney), or electronically with a qualified electronic signature (Art. 10(2)–(4) of the CPRB Rules). Foreign persons file with the central “Register” unit in Sofia.
4. Remedying deficiencies — within 7 days of notification (Art. 11(2)).
5. Decision — the Commission registers or refuses within 14 days of filing (Art. 18(1) ZKS; Art. 11(3) of the CPRB Rules).
6. Certificate — issued within 15 days of filing (Art. 19(1) ZKS) together with a control coupon; it states the group and categories or the types of works.

Refusals and removals must be reasoned and can be appealed under the Administrative Procedure Code (Art. 23 ZKS).

How to Check a Builder in the KSB Register

Anyone can search the public part of the register by company ID or name (Art. 31(6) of the CPRB Rules). At register.ksb.bg choose “Справки в регистъра” (register searches) and enter the UIC or at least three characters of the name. For each builder the register shows:

• the groups and categories or types of works for which it is registered;
• the certificate number and the Commission’s protocol;
• the validity of the control coupon;
• declared experience and financial information for the last three years.

Before awarding a contract, check not only that the company is registered but also that its group and category cover the specific project and that the control coupon is valid — the coupon is reissued every year after the procedure under Art. 20(2) ZKS (Art. 34(2) of the CPRB Rules). Removed builders appear in a separate list.

Obligations after Registration and the Art. 20(2) ZKS Procedure

• Annual procedure under Art. 20(2) ZKS. By law, the builder submits by 30 June each year data from its annual financial statements — net sales revenue, tangible fixed assets and average headcount — and pays the annual service price (Art. 21 of the CPRB Rules). For 2026, KSB announced a final deadline of 30 September 2026, 17:00 for the 2025 statements. Failure to file is a ground for removal (Art. 21(1)(4) ZKS), and a new application may be filed only after one year (Art. 22(2) ZKS).
• Keeping the category. If the latest statements no longer meet the criteria for the first, second or third category, the scope is brought into line (Art. 28 of the CPRB Rules). Without the minimum experience, KSB reduces the registration to the lowest category for which experience is proven.
• Changes in circumstances — to be filed within 14 days (Art. 20(1) ZKS). Failing to do so more than three times in a year is a ground for removal (Art. 21(1)(3)).
• Lost certificate — written notice to the Commission chair within 7 days (Art. 24 ZKS).
• Extending the scope — no earlier than three months after the last change and after the Art. 20(2) filing for the previous year (Art. 26 of the CPRB Rules).
• Inspections — at least 1% of registered builders are checked at random each year (Art. 41(1) of the CPRB Rules).

A builder is also removed upon dissolution, if it has not performed construction for more than three years, upon insolvency, or when it ceases to meet the requirements of Art. 15 ZKS (Art. 21(1) ZKS).

EU/EEA Builders

Temporary or one-off services

A builder entitled to build under the law of an EU or EEA state or Switzerland notifies the Commission of the specific project (Art. 25a ZKS; Art. 29 of the CPRB Rules). The notification includes a copy of the document proving its right to build, with an official Bulgarian translation, and a copy of the building permit or of the contract with the main contractor. The Commission issues a certificate for temporary or one-off services for that project, and the builder is listed in a separate list attached to the register.

Permanent activity

For permanent activity, a standard application for registration is filed with the central “Register” unit, together with the document proving the right to build and the documents under Art. 19(3) of the CPRB Rules, with official translations (Art. 17(3) ZKS; Art. 20 of the CPRB Rules). Equivalent insurance from another EU or EEA state is recognised under Art. 171a ZUT.

Penalties for Building without Registration

The head of the Directorate for National Construction Control (DNSK) imposes a financial penalty on the builder under Art. 237(1) ZUT:

The amounts are stated in leva in ZUT; the euro equivalents use the fixed rate (Art. 11(2) of the Euro Introduction Act). In addition, without a contract with a registered builder the site cannot be opened (Art. 157(2) ZUT).

Frequently Asked Questions