This literature review discusses diverticulosis, which is currently a crucial issue for modern healthcare worldwide due to its prevalence and variety of clinical courses. Diverticulosis of the colon can be uncomplicated and complicated and vary in its severity in different patients. Complications include inflammation of the diverticulum (i.e., diverticulitis), abscess formation, macro- and microperforation, and bleeding. Today, many researchers argue over pathogenesis and clinical course of complicated diverticulosis of the colon, a particular focus being on local immunity and colon microbiota, pathomorphological changes in the wall of the affected colon, as well as genetic alterations in patients with complicated diverticulosis. We describe risk factors and give modern overview of pathogenic mechanisms and pathological and predictive genetic markers of complicated diverticulosis. Keywords: diverticulosis, diverticular disease, complications, morphological and genetic predictors