The first regulation, which established an authorization system for the users of radioactive materials, was issued in Romania in 1962. As a result of developing radionuclides utilization in industry, medicine and research, a complex regulatory system, based upon a law adopted by parliament, which was later completed with a set of norms binding all users of radioactive materials, was established in 1974-1976. These norms are still valid. As part of this system, some criteria of exemption from authorization, especially those concerning the use of nuclear installations and radioactive sources, that are fulfilling a minimum of technical requirements, were settled. The main criterion of exemption is that the exposure of an individual members of the critical group should not exceed the limit of exposure permitted for individual members of public (which is 5 mSv/year). This paper presents the Romanian system of exemption from authorization. Application of this system is exemplified in the case of smoke detectors and electronic microscopes. (author). 7 refs, 1 tab.