INTRODUCTION AND OBJECTIVES: Partial (PN) or radical nephrectomy (RN) represents the standard of care for patients with small renal masses. Active surveillance (AS) may also be considered. We examined the rates of PN, RN and AS within a contemporary population-based cohort. METHODS: Using the Surveillance, Epidemiology and End Results database, we identified 26468 patients diagnosed with T1aN0M0 renal cell carcinoma, between years 1988 and 2008. Determinants of AS and PN were assessed using logistic regression analyses within surgically managed patients and within the entire cohort, respectively. RESULTS: Overall, 2797 (11%), 8966 (34%), and 14705 (56%) and patients underwent AS, PN, and RN, respectively. The rate of AS increased over time (from 2.4% in 1988 to 18.2% in 2008, P 0.001). Meanwhile, the rate of PN increased (from 4.7% in 1988 to 40.4% in 2008, P 0.001), while the rate of RN decreased over time (from 92.9% in 1988 to 41.4% in 2008, P 0.001). In multivariable analyses, the determinants of AS consisted of more contemporary year of diagnosis, more advanced age, male gender, decreasing tumor size, and unmarried marital status (all P 0.001). In comparison, the determinants for PN consisted of more contemporary year of diagnosis, younger patient age, male gender, Caucasian race, married status, and decreasing tumor size (all P 0.003). Regional differences for management of localized RCC were detected. CONCLUSIONS: AS may be considered in advanced age and infirm patients. It is noteworthy that a 5-fold increase was recorded for AS over the last two decades. Conversely, it is also encouraging that PN rate has increased in an 8-fold fashion, for the same time period.