A case of cytomegalovirus (CMV) vasculitis in the intestine of a patient with acquired immune deficiency syndrome (AIDS) is reported. The distal jejunum and ileum had multiple well-demarcated mucosal ulcers and microscopic examination revealed an unusual, exuberant fibroblastic proliferation in the ulcer base. Amidst these fibroblasts, there were several small blood vessels of which the endothelial cells contained cytomegalic inclusion bodies. The lesion showed a Kaposi's sarcoma-like appearance, but spindle cells were negative in immunostaining for factor VIII-related antigen or Ulex europaeus agglutinin-1. Although the CMV infection was observed in almost all organs, the exuberant fibroblastic proliferation seen in the intestine was not found in other organs. This lesion might represent a peculiar reaction of the immunologically compromised host to the CMV in the intestinal blood vessels.