The case of a patient with a giant renal calculus weighing 770 g in a solitary functioning kidney is reported. A 57-year-old man presented with right lumbar pain and macroscopic hematuria, and a giant stone was diagnosed in his right kidney. Nine days after a percutaneous nephrostomy placement, the patient underwent selective right renal angiography and transcatheter superselective embolization due to a sudden gross hematuria observed from both the nephrostomy tube and urethra. Embolization was successful. Right anatrophic nephrolithotomy was performed after stabilization of the patient. There were no complications during the recovery period. The case reported here is significant not only because it is the 7th biggest and the heaviest stone in the literature but also because it is the first giant stone reported to be in a solitary functioning kidney and treated without nephrectomy. Copyright (C) 2001 S. Karger AG, Basel.