The purpose of this study was to establish the feasibility of primary mini-access to the retroperitoneal space to perform certain retroperitoneoscopic procedures in which an enlarged port is not required for extraction of the specimen. Mini-laparoscopy or needlescopic laparoscopy has been performed in the past via the transperitoneal route, but this has not yet been reported for a retroperitoneoscopic procedure. Through a 5-mm primary access and 3- or 5-mm secondary ports, retroperitoneoscopic surgery was performed in seven adults for ureterolithotomy, renal biopsy, simple nephrectomy, nephropexy, cyst decortication, or drainage of a subphrenic abscess. The access technique used was a mini-version of a previously described percutaneous access technique with some modifications. The retroperitoneoscopic procedure was successful in all seven patients, and no complications developed. The operative time, blood loss, analgesic intake, and length of hospital stay were comparable with those of a standard retroperitoneoscopic procedure. However, the cosmetic results were better. Mini-retroperitoneoscopy is feasible and is a better alternative for patients in whom the whole procedure can be performed through 5-mm or smaller ports.