Various roentgen features of 19 cases of amebic colitis are analyzed and compared with granulomatous colitis, ulcerative colitis and other ulcerative diseases of the colon. The lesions of amebic colitis, in general, had a shaggy contour; the eccentric lesions were almost as common as the concentric lesions. The left-sided colitis was as common as the right-sided colitis and diffuse colitis was present only in the form of multiple skip lesions. Skip lesions were common. Deep and superficial ulcers of varying types were noted and had, in general, a ragged appearance. Various types of unspecific haustral and mucosal changes were noted. The annular lesions of amebomas were distinguished from carcinomas in most cases by their gradually tapering ends, relatively well preserved mucosa and response to antiamebic therapy. The diagnosis of amebic colitis was strongly considered when the cone-like cecum was accompanied by an intact terminal ileum and a skip lesion elsewhere in the colon. The shaggy contour of the lesions, the ragged ulcers, the multiplicity of the lesions, and a fairly well preserved mucosa on the postevacuation roentgenograms rendered further support to the diagnosis of amebic colitis. Two case reports are included to demonstrate the unique value of the therapeutic test (metronidazole), in the final and conclusive roentgen diagnosis of intestinal amebiasis. Included in the series also are cases of concomitant amebic colitis and ulcerative colitis, amebic colitis with amebic liver abscess, amebic colitis with intussusception, and amebic colitis with amebic diverticulitis.