&NA;Two cases of solitary rectal ulcer syndrome occurred in an 18‐year‐old woman and a 24‐year‐old man. Each had a history of bleeding on defecation, together with constipation alternating with diarrhea. In each case, a solitary rectal ulcer was noted by sigmoidoscopy and confirmed by both light and electron microscopic evaluations of biopsy material. Both clinical and pathologic features of these cases are compatible with classic rectal ulcer syndrome, which has been suggested to result from trauma followed by an ischemic event leading to fibrosis of the mucosa. Fibrosis in these two cases was confirmed by electron microscopy.