The majority of kidney cancer tumors are small renal masses (SRMs). Partial nephrectomy is now established as the preferred treatment modality. In some patients the potential morbidity may outweigh the oncologic risk. Based on active surveillance studies, restriction of radical therapy to patients with aggressive tumors has been proposed. This has spurred renewed interest in development of radiologic and biopsy-based diagnostic techniques that can identify high-risk disease. This article discusses the natural history and pathologic features of SRMs, the evolving role of biopsy, and provides an overview of outcomes of various treatment approaches and current recommendations for management.