Objective: Small, incidental renal masses are increasingly discovered in elderly patients with comorbid disease, such as chronic renal insufficiency (CRI). Observation of these masses or nephron-sparing surgery is the standard of care for these patients if possible. Laparoscopic renal cryotherapy (LRC) has been shown to be equivalent to laparoscopic partial nephrectomy in short-term follow-up for management of these masses. We evaluated the effect of LRC in this subset of patients and compared it with the effect in a group of patients who were undergoing the same procedure and who had normal renal function. Patients and Methods: Patients with CRI undergoing LRC for small enhancing renal masses were retrospectively evaluated for renal function changes after surgery. From February 2001 to July 2007, 123 patients underwent LRC; 77 of these had preoperative and postoperative creatinine levels (Cr) for evaluation, and 14 of these had renal insufficiency. Renal insufficiency was defined as a Cr level >1.3 mg/dL. Creatinine clearance (CrCl) was calculated by the Modification of Diet in Renal Disease equation. Complications were reviewed. Results: In patients with renal insufficiency, the mean preoperative Cr level was 2.39 mg/dL and postoperative Cr level was 2.24 mg/dL (P=0.0497); the mean preoperative CrCl was 32.3 mL/min/1.73 m2 and postoperative CrCl was 35.2 mL/min/1.73 m2 (P=0.034). In patients with normal function, the mean preoperative Cr level was 0.95 mg/dL and the postoperative Cr level was 0.93 mg/dL (P=0.33); mean preoperative CrCl was 78.6 mL/min/1.73 m2 and postoperative CrCl was 81.6 mL/min/1.73 m2 (P=0.19). Conclusions: LRC appears to have minimal impact on renal function as measured by serum Cr levels. LRC is nephron sparing and can be performed regardless of preoperative renal function.