Posttransplant body mass index (BMI) increase in kidney transplant recipients is an underestimated issue, predisposing to morbidity linked with development of polymetabolic syndrome. Aim The aim of the study was to assess the incidence of overweight and obesity among endstage renal disease patients before and after kidney transplantation. Material Four hundred eighteen kidney graft recipients were enrolled in the study which lasted a mean of 56 months. Inhabitants of Lower Silesia ( n = 3855) were used as controls. Overweight was defined as BMI between 25 and 30 kg/m 2 and obesity as >30 kg/m 2. Methods Mean BMI calculated in 418 patients, both pretransplant and after a 4.5-year observation period was compared with results of the Lower Silesian population. Results Mean pretransplant BMI in men ( n = 242) and women ( n = 189) was lower than in controls: men pretransplant BMI 24.3 kg/m 2 versus 25.7 kg/m 2 in the normal population; women, pretransplant BMI 23.17 kg/m 2 versus 25.2 kg/m 2 in the control group respectively. Mean total pretransplant BMI values increased from 23.82 to 25.9 kg/m 2 at last checkup (“last BMI”). A lesser posttransplant BMI increase was noted in men (7%) compared with women (9.6%). Before transplant, overweight or obesity occurred in 38% ( n = 157), after a 4.5-year observation period, 65% ( n = 232). Conclusions Our observations documented that obesity is a widespread issue in kidney graft recipients, affecting two thirds of the population. It should be the target of preventive measures and nonpharmacologic therapeutic interventions.