The CRO has a number of core functions:

The CRO is the statutory authority for registering new companies in the Republic of Ireland. The Office also registers business names. A business name is a trading name which differs from the names of the persons or the company who own the business.

Companies, and to a lesser extent business names, have an obligation under law to file certain documents with the CRO. These documents include details of changes of registered office, changes of company officers (director or secretary), or a number of other changes which affect the company. Companies are also required to file annual returns, and in most cases they must also file annual accounts. The CRO also keeps details of mortgages and charges imposed on companies.

Unfortunately, not all companies comply with their obligations to file documents. The CRO can take a number of measures to deal with companies who fail to file their annual returns, including prosecution of the company or directors, or striking the company off the register.

Companies who fail to file annual returns may be struck off the register of companies. If a company is struck off, the protection of limited liability no longer exists and individuals can be held personally liable for any debts incurred after strike off. Also, the assets of such a company will become the property of the State. While it is usually possible to reinstate companies which have been struck off, this can be an expensive process. Companies wishing to avoid such a fate should ensure that their annual returns are filed on time.

In 2019, over 5,068 companies were struck off the register for their failure to file annual returns. The programme of enforcement is ongoing.

Almost all of the information filed with the CRO is available for public inspection, usually for a small fee. Certain vital information, such as company name and registered office address, may be checked free of charge on the web search facility. A more detailed synopsis of a company is available by ordering a company printout or a copy of any document filed. This again can be obtained using the web search facility and a charge applies. Details of Business Names are also available using the search facility. Some basic statistics are available in the Annual Report. Please see Access to CRO Data page.

The Registrar of Companies is also the Registrar of Friendly Societies.

The Registrar of Friendly Societies is responsible for the assessment and registration of applications and any subsequent amendment of rules which societies are obliged to render to the Registrar, and to ensure that registered societies meet their statutory obligations with regard to filing returns, which once registered are made available for inspection by the public. In this regard the following three classes of body come under the remit of the Registrar of Friendly Societies: Trade Unions, Friendly Societies and Industrial & Provident Societies. The registry is available online to view but not all documents are scanned. It is possible to view the names and addresses of the registered Friendly Societies, Industrial and Provident Societies and Trade Unions along with a list of documents lodged against these entities.