Laparoscopy had significantly gained in the field of urologic surgery, almost all the surgical procedures in the retroperitoneal space being made, from the simple ones (renal cystectomy, varicocelectomy) to the ones requiring higher expertise (nephrectomy, adrenalectomy) by retro-peritoneoscopy and also transperitoneal. At the Surgery Department of "Sf. Ioan" Hospital, Bucharest, we approached initially the retroperitoneal pathology by lomboscopy, but afterwards we choose the transperitoneal approach because of the generous workspace and the clearer anatomical landmarks, regardless of the procedures (renal cystectomy, varicocelectomy, adrenalectomy, nephrectomy, pyelo-lithotomy, ureterolithotomy). In association with the Urology Department of "Sf. Ioan" Hospital we practiced two Hynes Andersen pyeloplasty for pyelo-ureteral junction stenosis by transperitoneal approach, using mini-laparoscopy tools. In one of the cases we also perform a basinetal lithotomy.