This article presents the oncological and medical rationale for partial nephrectomy as the treatment of choice whenever possible for T1 renal tumors. The value of partial nephrectomy in the management of small renal cortical tumors is gaining wider recognition thanks to (1) enhanced understanding of the biology of renal cortical tumors; (2) better knowledge about tumor size and stage migration to small tumors at the time of presentation; (3) studies indicating the oncologic efficacy of kidney-sparing surgery, and (4) increasing awareness of the wide prevalence of chronic kidney disease. The overzealous use of radical nephrectomy for small renal tumors must now be considered detrimental to the long-term health and safety of the patient with a small renal cortical tumor.