Exposed to sewage workers of a wastewater treatment plant and a control group in Thessaloniki, Greece, were examined for antibodies against hepatitis A (anti-HAV) and hepatitis B virus (HBV) infection markers. The main objective of this study was to investigate for epidemiological evidence so as to recommend vaccination of the occupationally exposed workers against these viral infections. Antibodies against hepatitis A virus were detected in 65.7% of the wastewater treatment plant workers and in 32.6% of the control group. The prevalence of anti-HAV was significantly higher in less educated persons and was increasing with age (p < 0.001), whereas in logistic regression analysis the adjusted seroprevalence of wastewater treatment plant workers was 3.5 times higher (p < 0.01) than the control population. Serologic evidence of past HBV infection was observed in 32.4% of the exposed to sewage population and in 5.8% of the controls. Multivariate analysis showed that variables significantly and independently related to previous HBV infection was occupational exposure to sewage (OR: 5.81; 95% CI: 2.07-16.29) and age over 40 years old (OR: 4.49; 95% CI: 1.51-13.33). These results support the vaccination policy of young and sensitive to hepatitis A and B virus wastewater treatment plant workers in our region.