Volume 22, Number 1Review ArticlesActive Surveillance for Small Renal MassesManagement ReviewShagnik RayJoseph G CheaibPhillip M PierorazioActive surveillance (AS) is a safe and reasonable management strategy for many patients with small renal masses (SRM) suspicious for a clinical T1a renal cell carcinoma based on excellent metastasis-free and cancer-specific survival. However, the expansion of robotic extirpation of SRM has outpaced the adoption of AS, resulting in the possibility of overtreatment for select patients with SRM, especially the elderly and comorbid. In this review of AS for SRM, with a focus on the Delayed Intervention and Surveillance for Small Renal Masses (DISSRM) Registry, we detail the rationale behind AS, review lessons learned from the past decades of literature, and offer suggestions for appropriate patient selection and follow-up. An improved understanding of the data supporting AS will empower physicians and patients to more comfortably pursue AS to avoid overtreatment and provide individualized care to patients with SRM. [Rev Urol. 2020;22(1):9–16] © 2020 MedReviews®, LLCRenal cell carcinomaSmall renal massActive surveillanceRenal mass biopsyChest imaging