Background. The aim of this study was to assess how retirement affects the short-term (up to 2 years after retirement) and medium-term (2-4 years) sport/exercise activity (S/EA) of Poles. To gain a broader context for interpretation, the effect of retirement on self-rated health status, attitudes, social activity, and sexual life was analysed. Methods. A quasiexperiment utilizing data from the longitudinal study Social Diagnosis and radius-matching method was conducted. Retiring men and women were matched with similar, nonretiring ones to make comparisons of differences in S/EA and other outcomes interpretable in terms of causality. Results. Retirement does not have a significant effect in the short term on S/EA of men (p=.440) and women (p=.340). The satisfaction of men with their health status in this period was improved (p=.007), although they more often declared health problems that impaired their everyday functioning (p=.045). Women rarely reported serious health problems (p=.024). In the medium perspective, retirement had the effect on reducing S/EA in men (p=.012) and various dimensions of their social life. Although men tend to worry more often about their health (p<0.001), they are less likely to suffer from problems with moving (p=.001) and fatigue (p=.013). Despite the fact that women are more often satisfied with their health (p=.027), they also more often complain about heart or chest pain (p=.010), body pain (p=.009), and fatigue (p=.007). Conclusion. It is necessary to prepare employees for retirement much earlier than in the preretirement age. In addition to raising awareness of the effect of S/EA functions, it is necessary to monitor the physical activity of employees and to use appropriate programmes for (1) maintaining motivation among employees who are physically active before they retire and (2) raising awareness and encouraging physical activity in employees who are physically passive.