Background: Health and safety at work is frequently perceived as a domain to be protected exclusively against occupational hazards without taking into account socio-demographic determinants and non-occupational factors dependent on work culture and quality of life. This study aimed at evaluating the impact of socio-demographic determinants on self-assessed health status and frequency of health complaints in workers employed in a large institution as well as the perception of the influence of working conditions on their health and the occurrence of selected diseases and health complaints. Material and Methods: The study was carried out in the entire population of employees of a large institution. Information that remained anonymous was collected using a questionnaire completed by the employees themselves. The strength of relationship was analyzed between the following three groups of variables: 1) self-assessed health status; 2) objectivized (based on reported facts) evaluation of health status; and 3) socio-demographic determinants. Results and Conclusions: The socio-demographic determinants have considerable impact on self-reported health status and frequency of health complaints and diseases linked and not-linked by respondents with working conditions. The frequency of responses indicating the relationship between work and health complaints were dependent on gender and duration of employment in the institution. The number of reported diseases and health complaints was influenced by gender, age, duration of employment and the respondents' level of education. Summing up, the following groups of respondents evaluated their health as worse than that of others: 1) persons aged over 50 years; 2) persons working 16 or more years in the institution, 3) persons with other than university education; 4) person with overweight. The results indicate that the health policy of institutions and enterprises should take into account socio-demographic determinants in the working population. Med Pr 2009;60(4):289-301