Squamous cell carcinoma of the renal pelvis is a rare tumour, mainly occurring in elderly patients with neglected and secondarily infected pyelocaliceal stones. It has a poor prognosis. The authors report the case of a 74-year old man with a destroyed and painful kidney containing a staghorn calculus for 30 years. The preoperative diagnosis was pyonephrosis, but nephrectomy, justified by the symptoms, showed that the kidney was invaded by a squamous cell carcinoma of the renal pelvis invading the psoas. The patient died 1 month after the operation. Treatment is essentially preventive by removal of staghorn calculi and management of chronic urinary tract infections.