We report a case of giant renal calculus 230 x 140 mm in size and weighing 1,350 g in a solitary functioning kidney treated by nephrolithotomy. A 47-year-old man presented with right lumbar pain, abdominal mass and microscopic hematuria. Physical examination revealed a stony hard mass on the right side of the abdomen, extending from the subcostal region to the iliac crest. A giant renal calculus in his right kidney and atrophic nonfunctioning left kidney was diagnosed by ultrasonography, IVP and CT scan. Right nephrolithotomy was performed. Analysis revealed a calcium phosphate stone. This case is the largest and the heaviest stone reported in the literature in a solitary functioning kidney. Copyright (c) 2007 S. Karger AG, Basel.