Between July 1990 and June 1996, 284 exposures to infectious material were reported by 247 health care workers (HCWs) at AHEPA University Hospital, Thessaloniki, Greece, representing an overall rate of 2.4% reported injuries per 100 HCWs/year. Nurses reported the highest rates of incidents (3.0%) and in all but one working group women exhibited higher injury rates per year than male HCWs. Young workers (21-30 years old) were primarily affected in incidents (P < 0.001). Needles were the most common implement causing injury (60.6%) and resheathing of used needles as well as garbage collection were common causes of injury. None of the HCWs seroconverted in exposures where immune status to blood-borne pathogens was estimated. Efforts by the infection control committee need to be more intense, in order to increase the rate of reported staff injuries. This will facilitate identification of unsafe practices and provide more adequate preventive measures.