An episode of lower gastro-intestinal haemorrhage in a patient, dialysed for chronic renal failure secondary to systemic AL amyloidosis, is described. The bleeding was due to angiodysplasia, but the presence of colonic amyloidosis complicated the diagnosis. The difficulties of diagnosing amyloidosis and angiodysplasia of the colon are discussed and other causes of colonic haemorrhage in patients with chronic renal failure and systemic amyloidosis are reviewed. The coexistence of amyloidosis and angiodysplasia of the colon has not previously been reported.