Objectives: Elective partial nephrectomy (PN) in patients with cT1b renal tumors is relatively unstudied. Most surgeons currently only perform radical nephrectomy (RN) in this population. Patients with localized kidney cancer may die from disease, but the risk of a noncancerrelated death is significant and may be worsened by nephrectomy-induced chronic kidney disease (CKD). PN may offer the perfect combination of cancer control and preservation of renal function; therefore we compared overall and cancer-specific survival in patients treated for cT1b renal masses. Methods: From 1999 to 1906, 510 patients with renal tumors >4-7 cm, a glomerular filtration rate (GFR) >60, and a normal contralateral kidney underwent extirpative surgery (PN, n = 212 or RN, n = 298) at our institution. As the patients were not randomized, we generated a propensity model based on preoperative patient characteristics to control for selection bias. Results: Cancer-specific survival was similar between cohorts when compared by pathologic stage and grade. On multivariate analysis, RN was associated with postoperative CKD (odds ratio 3.4, 95% confidence interval [CI] 2.1-5.6). Survival analysis demonstrated that when controlling for the propensity score, PN was associated with better overall survival (hazard ratio 0.30, 95% CI = .13-.71). Conclusions: Where technically feasible, PN offers cancer control equivalent to that of RN. Elective PN was associated with a significantly better overall survival in this cohort, even when controlling for age, tumor size, pathologic stage, and burden of comorbid diseases. The improvement in overall survival appears to be attributable in part to prevention of postoperative CKD.