Insulin resistance (IR) is the most significant risk factor for post-transplant diabetes mellitus (PTDM). This study aimed to determine the effects of regular physical activity on IR and PTDM in patients after kidney transplantation (KT). The study group (n = 22) participated in aerobic or combined sports (aerobic and anaerobic). Monitoring was provided by a sports tracker (Xiaomi Mi Band 4, compatible with the Mi Fit mobile application). Waist circumference was significantly lower (p = 0.0437, p = 0.0372), graft function was better (p = 0.0036, p = 0.0137), fasting blood glucose was lower (p = 0.0016, p = 0.0003), C-peptide level was lower (p = 0.0447, p = 0014) in the 3rd and 6th months of monitoring, and low-density lipoprotein was lower at 6 months (p = 0.0444) in the observed group than in the control group. IR was significantly lower at 6 months (p = 0.0202), and fasting blood glucose was significantly lower at 3 and 6 months (p = 0.0227) in the observed group. We confirmed the significant effect of regular physical activity on preventing the development of IR and impaired fasting glucose levels in patients after KT (Tab. 1, Fig. 4, Ref. 27). Text in PDF www.elis.sk Keywords: kidney transplantation, insulin resistance, physical activity.