Background: Renal oncocytoma accounts for 3 to 7% of all solid renal masses. Large renal oncocytomas (4 kg or more) are rare and only few cases are reported till date. Case Report: A 44 year old man presented with sudden onset right flank pain and large right abdominal lump. Further evaluation revealed a large heterogeneous mass not seen separately from right kidney. Intra-operatively a huge right renal mass (approximately 20 cm and 4.5 kg in weight) along with areas of necrosis and hemorrhage, completely replacing renal parenchyma was seen. Histopathology and immunohistochemistry was suggestive of oncocytoma. Conclusion: The renal oncocytoma can be differentiated from malignant RCCs by histopathology and immunohistochemically.