BACKGROUND Healthcare workers are known to be prone to infection with the hepatitis B virus. We did this study, as there are only a few reports from India on the prevalence of this infection among hospital personnel, so that a rational and effective immunization policy could be evolved. METHODS Eight hundred and sixty-three hospital employees including doctors, nurses, technicians, office workers, orderlies and other ancillary staff were screened by ELISA for both hepatitis B surface antigen and its antibody as indicators of prior infection. RESULTS Eighty-six (10%) were found to be seropositive for hepatitis B surface antigen alone while in 138 (16%) only the antibody was detected. We did not come across any subject in whom both the antigen and the antibody were present simultaneously. Seropositivity was associated with a history of contact with blood or blood products, accidental parenteral exposure and direct patient contact. A history of close contact with a known patient with hepatitis and a past history of jaundice showed a weaker association, while a history of surgery or dental treatment was not significantly associated with seropositivity. There was a significantly (p < 0.5) higher seropositivity in males than in females. The seropositivity was also related to the employee's socio-economic status. Working in a dialysis unit carried the greatest risk. CONCLUSIONS Energetic steps should be taken in all hospitals for the prevention of hepatitis B virus infection among healthcare workers.