Calcifications of renal masses are common. They are usually dense, partial, small, punctate, and linear opacities. Diffuse calcification is an extremely rare feature of renal masses. Generally, calcified renal cell carcinomas are hypovascular, with calcifications in the interstitium, and they also contain fibrotic capsules, necrotic areas, or hyalinization. We recently observed a renal neoplasm with diffuse calcification on CT and intermediate vascularity on angiography, which was diagnosed histologically as renal cell carcinoma, clear cell type. Interestingly, there were numerous calcific deposits within the tumor cells.