A CRO number is a unique registration number assigned to every company registered with the Companies Registration Office in Ireland. It is a numeric identifier (typically 5–6 digits) that never changes, even if the company changes its name. Here is how to find it and what it is used for.
What Does CRO Stand For?
CRO stands for Companies Registration Office, the statutory body in Ireland responsible for registering companies and maintaining the public register of company information. The CRO operates under the Department of Enterprise, Trade and Employment.
What Does a CRO Number Look Like?
A CRO number is a numeric identifier, typically between 5 and 6 digits. For example:
- Google Ireland Limited: 368047
- Ryanair DAC: 104547
There is no prefix or suffix — just the number. Some older companies have shorter numbers (3–4 digits), while newer companies may have 6+ digits.
How to Find a Company's CRO Number
Method 1: Search on Businesses.ie
Use our company registration number guide and search. Search by company name and the CRO number is displayed on every company profile page alongside the company name and status.
Method 2: CRO CORE System
Search on core.cro.ie — the CRO's official online system. Enter the company name and the registration number will appear in the search results.
Method 3: Company Documents
The CRO number appears on every official company document: annual returns, certificates of incorporation, and company letterheads (companies are legally required to display it).
Method 4: Company Letterhead and Website
Under the Companies Act 2014, every Irish company must display its CRO registration number on:
- All business letters and emails
- Order forms
- The company website
- Invoices
What Is the CRO Number Used For?
- Uniquely identifying a company: Multiple companies can have similar names, but each has a unique CRO number
- CRO filings: All forms submitted to the CRO reference the company's registration number
- Revenue (tax): The CRO number is used when registering for tax
- Due diligence: Searching by CRO number is the most reliable way to find the correct company — names can be similar, but numbers are unique
- Legal proceedings: Court documents identify companies by their CRO number
CRO Number vs. Tax Reference Number
The CRO number is not the same as a company's tax reference number (issued by Revenue) or its VAT number. They are separate identifiers for separate purposes:
| Identifier | Issued By | Purpose |
|---|---|---|
| CRO number | Companies Registration Office | Company registration |
| Tax reference number | Revenue Commissioners | Corporation tax, PAYE |
| VAT number | Revenue Commissioners | Value Added Tax |
Can a CRO Number Change?
No. A CRO number is assigned at incorporation and never changes, even if the company changes its name, address, directors, or company type. If a company is struck off and later restored, it retains the same CRO number.
Summary
A CRO number is a unique numeric identifier assigned to every Irish registered company by the Companies Registration Office. It never changes. Find it by searching on Businesses.ie, on CORE, or on the company's own website and correspondence. It is not the same as a tax reference number or VAT number.