Radiofrequency ablation is a safe and effective treatment for small renal-cell carcinoma (RCC) in selected patients. After ablation, computed tomography or magnetic resonance imaging is used to confirm complete eradication or the presence of residual unablated tumor. The characteristic findings associated with these imaging techniques have been described previously. When the appearance of the ablated tumor deviates from expected findings, percutaneous biopsy is necessary to further evaluate the ablation zone. The present report describes three patients whose atypical findings after ablation of small RCC prompted percutaneous biopsy.