The study describes the use of postexposure antiretroviral prophylaxis (PEP) after occupational exposure to HIV in Denmark in the period 1/1 1997-31/12 1998. Forty-seven accidentally exposed persons received PEP in this period, of whom 14 were nurses, 13 physicians and 11 were not employed in the health care system. In 23 cases side effects to PEP were described. In 18 cases the index person was i.v. drug abuser and in 11 cases homosexual/bisexual men. In 18 cases the HIV status of the index person was unknown at the time of exposure. Ten of these index persons were subsequently tested and all found HIV-negative. It is concluded, that the frequency of occupational exposure to HIV is unacceptably high. Further it is emphasised that in cases where the HIV status of the index person is unknown, PEP should only be instituted if the index person is at risk of being HIV infected and has signs of HIV infection.