From 1967 to 1985 conservative surgery (enucleation, n = 49; partial resection, n = 7) was performed for renal tumors in 57 patients (age 31-77, mean 54.8 years). Imperative indications for conservative surgery (n = 29) were chronic renal failure, benign pathology of contralateral kidney, functional or anatomical solitary kidney, and bilateral tumors. Elective conservative surgery (n = 28) was done for small, peripherally located lesions, in cases of uncertain malignancy and in one tumor detected by chance during stone surgery. Tumors removed for imperative indications were 2-11 cm (mean 5.8 cm) in size. In the elective group, tumor size ranged from 1 to 7 cm (mean 3.3 cm). Follow-up was 6-103 months (mean 35.8 months). In the group with imperative indications, there was 1 postoperative mortality; 18 of 29 patients are alive without evidence of disease, 2 with metastases, and 2 were reoperated conservatively for local recurrences; 1 was lost to follow-up, 2 died of metastases, and 3 died due to unrelated reasons. In the elective group all 28 patients are living free of cancer.