Renal mass biopsy (RMB) is a safe and accurate method for diagnosis and clinical management of renal masses. However, the non-diagnostic rate is a limiting factor. We tested the hypothesis that imaging characteristics and anatomic complexity of the mass may impact RMB diagnostic outcome using the preoperative aspects and dimensions used for an anatomical (PADUA) classification and radius-exophytic/endophytic-nearness-anterior/posterior-location (RENAL) score.