Two clinico-morphological forms of colon diverticulosis are distinguished on the basis of post-mortem and surgical material (89 observations) studied histologically, neurohistologically and electron-microscopically. The first form is characterized by the disturbance of colon peristalsis, inflammation, segmentation of the colon wall and the presence of staged changes in the colon wall muscles. Disturbances of the vegetative innervation and regional hemodynamic disturbances play a role in the patho- and morphogenesis. The second form develops in aged persons and is characterized by weakness of the colon wall with thinning of the muscle layer. In both forms atrophy of the circular muscle layer develops with dilation of perivascular spaces and formation of "weak sites" in the colonic wall.