Our aim was to characterize the clinical spectrum of anorectal dysfunction among eight patients with progressive systemic sclerosis (PSS) who presented with altered bowel movements with or without fecal incontinence. The anorectum was assessed by physical examination, proctosigmoidoscopy, and anorectal manometry. There was concomitant involvement of the other regions of the digestive tract in all patients as determined by barium studies, endoscopy, or manometry: eight esophageal, three gastric, four small bowel, and two colonic. Seven patients had fecal incontinence, and four also had second-degree complete rectal prolapse. Abnormal anorectal function, particularly abnormal anal sphincter resting pressures, were detected in all patients; anal sphincter pressures were lower in those with rectal prolapse. Rectal capacity and wall compliance were impaired in seven of seven patients. Successful surgical correction of prolapse in three patients resulted in restoration of incontinence for six months and seven years in two of the three patients. We conclude that rectal dysfunction and weakness of the anal sphincters are important factors contributing, respectively, to altered bowel movements and fecal incontinence in patients with gastrointestinal involvement by PSS. Rectal prolapse worsens anal sphincter dysfunction and should be sought routinely as it is a treatable factor aggravating fecal incontinence in patients with PSS.