Recent years, obesity is a growing health problem also in patients with chronic renal failure and end it's end stage. This situation has a negative impact both on the extension of the waiting period for transplantation, and the survival rate of the transplanted organ and the recipient. Weight loss through lifestyle modification before transplantation is ambiguous. Its well known fact of rapid body mass gain after transplantation, and finally the results of transplantation are not better than those of patients who have not reduced body weight. The paper presents preliminary experience associated with bariatric operations of three chronic dialysed patients with morbid obesity BMI> 35 kg/m², all patients had been treated by Roux-en-Y gastric by-pass (RYGB). All operated patients were classified as potential recipients were listed by Poltransplant. One of them three months after RYGB surgery underwent without complications a renal transplantation. Preliminary experiences based on operating these three case confirmed the complete safety of this type of approach in patients with end-stage chronic kidney disease (CKD).