Background: The objective of the study was to collect the data on undetected hepatitis B virus (HBV) in the frequently hospitalized (at least twice in the last 5 years) population of the Kujawsko-Pomorskie voivodship. The study results could be used by occupational health services and local governments to take preventive actions. Material and Methods: The study focused on empirical data derived from hepatitis B Screening Programme in the Kujawsko-Pomorskie voivodship. The study comprised 6332 people tested for hepatitis B virus surface antigen – HBsAg. They had been hospitalized at least twice. The diagnostic survey was based on an anonymous questionnaire, developed for this study. For the statistical analysis the Statistica 10.0 program was used. A level of statistical significance was assumed at a value of α = 0.05. The results showing that the probability test p satisfy the inequality p < 0.05 were considered to be statistically significant. Results: HBs antigen was detected in 34 patients (0.54%). There was no association between the detected infections and the gender of the respondents. There was no relationship between the detected infections and transfusion of blood and blood products before 1992. Surgical procedures performed in the patients did not increase the risk of hepatitis B infection. Conclusions: Actions aimed at detecting asymptomatic infections should primarily focus on the 35–39 age group. Effective identification of chronically-infected people and application of optimal treatment play a key role in reducing the risk of disease progression in the whole population. Therefore, the implementation of screening programs is warranted for prevention and early detection of hepatitis B. Med Pr 2014;65(6):777–784