January 2025—Renal mass biopsy has become an indispensable pre-management diagnostic tool, especially as incidental renal masses are increasingly detected with modern imaging techniques. It offers the patient the opportunity to get a definitive diagnosis without necessitating nephrectomy, especially helpful for patients with advanced disease or those who are poor surgical candidates. This is crucial, as certain renal cell carcinoma (RCC) subtypes have significantly different prognostic outcomes and therapeutic implications, making it essential to subtype RCCs in addition to distinguishing between benign and malignant lesions. For instance, systemic treatment strategies diverge markedly between clear cell RCC and non-clear cell RCC subtypes, underscoring our role in guiding personalized therapy choices. This article synthesizes key findings and diagnostic challenges most encountered on renal mass biopsy, with a focus on clear cell RCC, clear cell papillary renal cell tumor, TFE3-rearranged RCC, papillary RCC, oncocytoma, and chromophobe RCC.