Due to the growing concern of Health Care Workers (HCW) regarding the possibility of acquiring blood borne infections through accidental occupational exposure and the fact that HIV and Hepatitis B infections have occurred in that setting, an evaluation of the frequency of accidents and their circumstances, suffered by HCW with blood or body fluids from patients was carried out. 1,340 self administered questionnaires were given to HCW with direct contact with patients in a general 800 beds hospital, requiring information of accidental percutaneous, mucosal or cutaneous (it not intact) exposures to blood or certain (risky) body fluids ever and/or in the last 6 months. Sixty five percent of HCW referred some exposure ever and 46% in the last 6 months. The rate of exposure ever ranged from 36.6% in medical students to 69.5% in doctors, 78.5% in nurses to 100% in dentists. Seventy seven percent of the exposures were seen during routine care, 28.5% were perceived as due to personal carelessness, 19.9% due to patient agitation, 33.5% as inherent to the procedure and 8.9% to abandonment of material. Exposures were mostly to blood. One hundred eleven out of 331 (33.5%) exposures were produced during handling of syringes; 33.2% during invasive procedures and 13% during cleaning of material. Sixty out of 107 (56%) non surgical doctors (NSD) and 61/67 (92.5%) of surgical doctors (SD) had had exposures ever (p < 0.01), 16.8% and 65.6% had had one or more in the last 6 months respectively.(ABSTRACT TRUNCATED AT 250 WORDS)