The risk of HBV infections in health workers and the different prevalence according to the hospital activities has been shown in a great number of papers. In order to establish the prevalence of serological HBV markers in health workers fron high complexity hospital, we have analyzed 730 inquiries refilled in the period 1994-1995 before receiving the antihepatitis B vaccine. We studied 730 health workers, 282 (38.8%) males and 447 (61.2%) females with a mean age of 40.1 years old. We found 75/730 (10.2) serums antiçHBc reactives. The found prevalence was significantly larger than the one found in blood donors. The analysis of the prevalence according to the hospital activities showed that the infirmary personnel is the only with anti-HBc prevalence significantly superior to the blood donors, and the other health workers prevalence. Differences in the anti-HBc prevalence between the physicians specialties were not found. Our results agree with other publications that clearly show that health workers are a risk group for HBV infection. However, what attracts attention in the analyzed population is that the only ones with anti-HBc prevalence significantly superior to the blood donors' and the other health workers prevalence were the nurses, suggesting that nurses are the only health workers that have risk of HBV infections.