Syphilis of the rectum is rare, and cases with primary chancre of the rectum are seldom observed clinically. Therefore, reports of substantiated cases of rectal chancre have appeared in the literature infrequently. This may be due less to their low incidence of occurrence than to (1) failure to consider syphilis as a diagnosis along with the more usual other rectal conditions that share a clinical resemblance; (2) self-treatment by patients who consider their symptoms due to hemorrhoids, rectal irritations, and so on; (3) avoidance of medical attention because of fear of being discovered as sexual deviates, and (4) failure of physicians to consider the rectum as a possible site for primary syphilitic infection when confronted with positive results from serologic studies or manifestations of secondary syphilis. Since chancre of the rectum is acquired most often through the practice of pederasty, if the high incidence of homosexuality