The natural history of extraperitoneal gas present in the operative bed was prospectively evaluated with serial computed tomography in 25 renal transplant patients. While 73% (11/15) of patients studied within the first 4 days after drain removal had residual gas in the operative bed, 90% (9/10) of patients examined after the 5th day had no demonstrable gas in the peritransplant area. Of 12 patients with gas present on the initial scans, follow-up studies documented resolution of the gas in 10 with subsequent benign clinical courses. In the remaining two patients, the gas collections increased in volume on serial examinations followed shortly by wound dehiscence. Our data suggest that gas present later than 1 week following drain removal should prompt careful scrutiny and that an increase in the volume of gas collections on serial studies must be considered pathologic. The incidence and significance of peritransplant fluid collections in these patients are also discussed.