Background: Our paper presents the problem of exposure to potentially infectious material among health care workers, and also in police officers, prison guards, cleaning service personnel and ordinary citizens. Materials and Method: In the study period, 200 patients were admitted to the Infectious Diseases Clinic after exposure to potentially infectious materials in order to evaluate the risk of HBV, HCV and HIV infections and initiate post exposure prophylaxis. HBsAg, a-HCV and a-HIV were carried out on the day of admission, a-HBs was measured in patients who had been vaccinated against hepatitis B virus. Clinical evaluation of HBV, HCV, HIV infections was performed in the source patients' plasma. Results: The study population consisted of 93 health-care workers (63 nurses, 25 physicians, and 5 medical students), 30 policemen, 23 prison guards, 42 cleaning service workers employed in health-care centers. The remaining 12 patients were inhabitants of the Łodź region who had not been occupationally exposed to potentially infectious material. Conclusions: Although "safe needles" are in use, exposure among health care personnel still occurs. The problem of occupational exposure among police officers and prison guards is highly underestimated. The lack of control over the vaccination against hepatitis B virus in groups not related with health care creates the risk of new infections. Med Pr 2010;61(1):15-23