A patient in whom Salmonella typhimurium infection caused a localised colitis is described. Colitis has been demonstrated in experimental animals infected with S. typhimurium and noted at post mortem in patients dying from S. typhimurium infection. However colitis is an infrequently recognised feature of this infection in man, the usual diagnosis being one of gastroenteritis. There have been four other cases reported with radiological evidence of colonic involvement due to salmonella infection. Colitis probably occurs more frequently than is usually recognised in this condition and must be distinguished from ulcerative colitis.