Objectives: The research aims to assess the level of physical activity among administrative, technical, and manual workers employed in Warszawa public institutions and to analyze the factors that increase the risk of failing to meet World Health Organization (WHO) recommendations. Material and Methods: The study comprised 373 employees of randomly selected institutions. A short version of International Physical Activity Questionnaire (IPAQ) was applied. The correlation between the mean values of duration, days, MET-min/week of efforts, gender, and type of work was analyzed using the Tukey’s honest significant difference (HSD) test, while the correlation between the level of physical activity and the socio-demographic characteristics was assessed with the Chi² test. The strength of the relationship between socio-demographic characteristics and fulfilment of WHO standards was expressed by the odds ratio (OR) and 95% confidence interval (95% CI). The significance level was p = 0.05. Results: High levels of physical activity were declared by 41.8% of the manual workers, 14.7% of the administration staff, and 7.3% of the technicians; 19%, 31.5% and 54.5%, respectively, reported low levels of physical activity. Factors determining the fulfilment of the WHO recommendations include: the nature of work (p = 0.003), education (p = 0.004), and income (p = 0.003). The risk of being inactive nearly doubles in the case of administration staff (31.5%) and increases more than 4 times in the case of technicians (54.5%). Respondents with secondary school education (31.6%) are exposed to a 3-fold higher risk of inactivity, while in respondents with higher education (37.2%), the level of the risk is 4-fold higher. Compared to those in the highest income group (23.4%), people who earn less (34.1%) are inactive almost twice as often. Conclusions: Urgent intervention is necessary in all studied groups: increased energy expenditure for recreation and locomotion, educational offers of employers to promote healthy lifestyle, management of leisure time budget, and strategies for changing behavior.