The purpose of this study was to evaluate the duration and clinical significance of postoperative pneumoperitoneum (PP) after laparoscopic nephrectomy. We reviewed consecutive laparoscopic nephrectomies from 2001 to 2007. The presence and timing of free intraperitoneal air was documented. Postoperative imaging was performed in 135 of 538 patients with 55 patients (41%) noted to have free air. These included 53 hand-assisted laparoscopic nephrectomies and 2 purely laparoscopic radical nephrectomies. There was no difference between patients with and without PP with respect to age, sex, race, length of hospital stay (LOS), operating room time, earliest postoperative film with PP, presence of free air on plain film, or complication rate (P>0.05). Donor nephrectomy patients had the highest incidence of PP (P=0.01). Nineteen patients had benign PP (34.5%) at least 3 days after surgery with the longest interval postsurgery being 9 days. Postoperative free air after laparoscopic nephrectomy is common, even up to 9 days after surgery.