The computed tomographic (CT) findings of fourteen patients with inflammatory disease and 28 with neoplasm, who had an abnormal colonic wall thickening, were retrospectively studied to establish CT criteria for each disorder in differentiating inflammatory from neoplastic lesions. According to homogeneity, density and contour of mural thickening and pericolic inflammatory change in enhanced CT scans, we classified colonic wall abnormalities into 6 patterns : 1)multilayering with inner and outer hyper and middle hypodensities, II)homogenously hyperdense with pericolic inflammatory change, III) heterogeneously hyperdense with pericolic inflammatory change, IV) homogeneously hyperdense with lobulated contour, V) heterogeneously hypodense with lobulated contour and VI) heterogeneously mixed densities with irregular lobulated contour, Type I, II, and III were distinctively identified in inflammatory disease, type IV, V in neoplasm, and type VI in both diseases. We conclude that enhanced CT could be helpful in the initial diagnosis and / or suggestion of abnormal colonic wall diseases and differentiation of inflammatory from neoplastic diseases.