SummaryA 22-year-old male with obstructive uropathy and renal failure was given pre-operative haemodialysis. He collapsed five hours later. Autopsy revealed massive intrarenal haemorrhage and rupture of a dilated superior calyx intraperitoneally. Anticoagulation employed during haemodialysis was probably responsible for this spontaneous renal haemorrhage and subsequent calyceal rupture.