PURPOSE: To assess epidemiologic characteristics, clinical and pathologic patterns of presentation, and treatment strategies in a contemporary population with renal masses (RMs).METHODS: The Clinical Research Office of the Endourological Society collected prospective epidemiologic, clinical, and pathologic data on consecutive patients with RMs who were treated during a 1-year period in 98 centers worldwide. Preoperative assessment and treatment were performed according to local clinical practice guidelines.RESULTS: From January 2010 to February 2012, 4288 patients (4355 cases, 4815 tumors) were treated for a RM. The mean age of the cohort was 61.5 years, and the ratio male:female 1.8:1. Caucasians represented 75% of the population, and the median body mass index was 27. The cohort exhibited a high rate of comorbidity (65.6%), including a 48.5% rate of hypertension; one-third of patients had a combination of two or more comorbidities. One-third of patients (36%) had risk factors for renal-cell carcinoma (RCC), of which smoking and obesity were the most common. Diagnosis was incidental in 67% of cases, and 22.2% of cases had chronic kidney disease stage ≥III at presentation. Median radiologic size was 44 mm (range 2-300 mm) and 68% were cT1. Radical nephrectomy and nephron-sparing surgery (NSS) including ablation were performed in 52% and 46% of cases, respectively, while 3.6% of cases were actively surveyed. Median pathologic size was 43 mm (range 2-300 mm) and 63% of the RCCs were pT1.CONCLUSIONS: Current patterns of presentation of RMs are consistent with the decreasing trends in age and clinical or pathologic size and increasing incidental diagnosis. Patients exhibit a considerable basal comorbidity and presence of risk factors for RCC. Half of the cases are treated by a nephron-sparing modality with an increase in the penetration of NSS techniques in the contemporary urologic practice.