We evaluated a patient cohort with renal tumors 4 cm. or less treated with partial or radical nephrectomy. We compared patient and tumor characteristics, and survival in these 2 groups. We retrospectively analyzed the records of 670 patients with a median age of 63 years treated surgically for renal cell carcinoma between July 31, 1989 and July 31, 1997. Renal tumors 4.0 cm. or less were noted in 252 patients (38%) who underwent a total of 262 procedures, including 183 radical (70%) and 79 partial (30%) nephrectomies. Ten patients required 2 operations each because of bilateral renal cell carcinoma. Median followup was 40 months. We compared clinicopathological parameters in the partial and radical nephrectomy groups using chi-square or Wilcoxon analysis as appropriate. Survival analysis was determined by the log rank test and Cox regression model. The partial and radical nephrectomy groups were comparable with respect to gender ratio, tumor presentation, histological classification, pathological stage and complication rate. Median tumor size was 2.5 and 3.0 cm. in the partial and radical nephrectomy groups, respectively (p = 0.0001). Resection was incomplete in 1 patient (1.3%) in the partial and none in the radical nephrectomy group. There was no local recurrence after either procedure, and no significant difference in disease specific, disease-free and overall survival (p = 0.98, 0.23 and 0.20, respectively). Patients with a small renal tumor have similar perioperative morbidity, pathological stage and outcome regardless of treatment with partial or radical nephrectomy. Therefore, partial nephrectomy remains a safe alternative for tumors of this size.