Glomus tumors are uncommon benign perivascular neoplasms that have rarely been described outside of their usual peripheral soft tissue sites. We report a unique case of glomus tumor of the renal pelvis in a 53-year-old woman who presented with microscopic hematuria associated with obstruction of the ureteropelvic junction and marked hydronephrosis. At initial gross examination, the tumor mimicked a urothelial carcinoma.