The route of HIV transmission are now well defined. For health care workers the major occupational risk is from parenteral exposure to infected blood or other body fluids. To prevent such exposures, it would be prudent for HCWs to assume that all patients are potentially infected and a set of precautions applicable universally be followed in contacts with all patients. The provisions of "Universal Precautions" apply to blood, CSF, genital secretions and all body fluids. It is essential that barrier protection and washing of hands be practiced, body fluids be handled with care, correct sterilization and disinfection procedures be followed and a suitable system of waste disposal be evolved. Although the Universal Precautions have been useful in abating some of the more extreme behavior associated with treating AIDS patients and in establishing a rational approach to infection control, some of the recommendations have not been found to be efficacious or cost effective. Preventive measures recommend on the basis of demonstrated efficacy and aimed at routes of exposure that represent true risk are needed. The risks for occupational infection with blood borne pathogens have been a source of concern for health care workers (HCWs) because of their frequent and often substantial exposure to patient blood and body fluids. HCWs have long been identified as a group "at risk" for occupationally acquired Hepatitis B infection. With the development of acquired immunodeficiency syndrome (AIDS) epidemic, both HCWs and policy makers have become increasingly concerned about occupational risk from blood borne infections.(ABSTRACT TRUNCATED AT 250 WORDS)