The incidental finding of a small renal mass poses a therapeutic dilemma. The traditional treatment of clinically important masses has been radical nephrectomy. Recently, nephron-sparing surgery has emerged as a viable alternative; and experimental minimally invasive percutaneous tissue ablation techniques, including cryotherapy and radiofrequency ablation, are being evaluated. In this review, we discuss the dilemma posed by frequent renal imaging and the increased proportion of incidental tumors being detected, the limitations of needle biopsies for histologic diagnosis, nephron-conserving and minimally invasive surgery, and the possible merits of radiofrequency ablation and cryotherapy. We envision a defined role for minimally invasive percutaneous or extracorporeal ablation of small renal tumors.