Population health and its determinants are one of the major challenges to social and economic policy. The aim of this study was to investigate the relationship between occupational activity and biological condition in adult working Polish men. The participants of the study were 300 men (30-65 years), healthy inhabitants of the city of Wroclaw, Poland. Seventeen measures of biological condition were examined. The subjects were divided into three different occupational groups: professionals, soldiers and skilled workers. A comparison of biological age profiles of three occupational groups showed that in the majority of characteristics, professionals had the youngest biological age, whereas skilled workers had the highest biological age. The results for soldiers were not as unambiguous, but biological parameters were generally closer to those for professionals. Inborn biological predispositions and long-term impact of the working environment can influence on the biological condition of various professional groups. Knowledge of the determinants of biological condition might result in efficient use of predisposition to work or may be of help in extending their time of work ability.