Cross-sectional imaging shows a limited diagnostic accuracy for the histological discrimination of small renal masses (SRM). In this scenario, a renal tumor biopsy is a safe, feasible and effective diagnostic tool that can guide treatment strategy by providing the histological characterization of a SRM. Although nephron-sparing surgery is still considered the gold standard treatment for patients with SRM, more and more evidence suggests that active surveillance (AS) is a reasonable alternative option, especially in old and comorbid patients. Indeed, owing to the relatively slow growth and favorable biology of SRM, AS followed up by, if necessary, a delayed intervention provides an optimal oncological outcome with low rates of systemic progression or death.