Myxoma is a rare mesenchymal tumor and it is mainly seen in heart and skin. Renal myxoma is extremely rare. To date, eleven cases of kidney myxomas have been reported in the literature. One of them is myxoma of the renal sinus. Our case was an 82-year-old man admitted to our hospital symptoms related to the urinary tract obstruction. Abdominal computerized tomography revealed a solid, hypodense mass 9 cm in diameter infiltrating the renal parenchyma in the renal pelvis. The patient underwent nephrectomy. The resected kidney contained gelatinous tumor with indistinct borders. The tumor was composed of slender, bland, spindle-shaped cells with large amounts of mucoid material. Tumor cells were positively stained with vimentin, focally stained positive for smooth muscle actin and had negative reactivity for S-100 protein, epithelial membrane antigen and pancytokeratin. Herein we report the second case of renal myxoma arising from the renal sinus.