This study was aimed at investigating the characteristics of occupational accidents and of the workers that suffered them, and at evaluating the adhesion to chemoprophylaxis and to control and follow up tests after occupational accidents with risk of contamination by the human immunodeficiency virus and of the hepatitis B and C virus. This is a descriptive epidemiological study whose data was collected from the notifications of one of the administrative regions of the State of Sao Paulo's Secretary of Health between 2000 and 2001. It was observed 7.3% of refusals for chemoprophylaxis against human immunodeficiency virus by anti retrovirals, and that 40.6% of the care workers who accepted the chemoprophylaxis did not complete the treatment in the four weeks estimated for it. This diagnosis highlights the need for the institutions involved to establish strategies that make possible an increase in the adherence of health workers to these care procedures.411120126