Purpose: We examined outcomes in patients with recurrent or de novo renal lesions treated with repeat partial nephrectomy on a solitary kidney. Materials and Methods: We reviewed the records of patients who underwent nephron sparing surgery at the National Cancer Institute from 1989 to 2008. Patients were included in analysis if they underwent repeat partial nephrectomy on a solitary kidney. Perioperative, functional and oncological outcomes were assessed. Functional outcomes were evaluated using the Modification of Diet in Renal Disease equation for the estimated glomerular filtration rate. Oncological efficacy was examined by the need for subsequent repeat renal surgery and the development of metastatic disease. Results: A total of 25 patients were included in the analysis. A median of 4 tumors were resected. Median estimated blood loss was 2,400 ml and median operative time was 8.5 hours. Perioperative complications occurred in 52% of patients, including 1 death and the loss of 3 renal units. There was a decrease in the estimated glomerular filtration rate at followup visit 1 within 3 months after surgery but at 1-year followup the difference was not significant (p <0.01 and 0.12, respectively). Surgical intervention was recommended in 8 patients (38%) for recurrent or de novo tumors at a median of 36 months. The average metastasis-free survival rate in the cohort was 95% at 57 months (median 50, range 3 to 196). Conclusions: Repeat partial nephrectomy in patients with solitary kidney is a high risk alternative. The complication rate is high and there is a modest decrease in renal function but most patients remain free of dialysis with acceptable oncological outcomes at intermediate followup. © 2010 American Urological Association Education and Research, Inc.