Objective: To study the morphological factors in the structure of the abdominal part of the colon and perineum in anorectal malformations in children. Material and methods: In 10 patients (1 day-2, 5 years) with anorectal developmental defects, a complex histological study of myo- and neurostructures of abdominal fragments from the rectum was performed, which were removed during surgery, with proctoplasty for the correction of the congenital pathology of the anorectal region. The study group consisted of 2 patients with unsupported forms of vice, 7 patients with fistula in the urinary system and one child with fistula per perineum. Results of the study. The search for the study was focused on revealing the fibers of the transversely striated muscle tissue of the subcutaneous part of the external anal sphincter, as one of the factors of its structure (presence). It was determined that the structural elements of the structure of the perianal region and pelvic floor in children with anorectal defects have certain morphological features, namely: the skin and subcutaneous fat, at the location of the necessary location of the external anus, in 80% of cases did not contain the muscular elements of the surface part of the external anal sphincter; the wall of the apical part of the rectum was characterized by hypoplasia of the mucosa and in most cases of the muscle layer with the fullness of their vessels and the presence of autonomic intermuscular ganglia. Conclusion. The structural elements of perianal area and pelvic bottom anatomy of children with аnorectal development defestes have morphological peculiarities are certain, namely: in the place of needed location of external anal hole the skin and hypodermic-fatty cellular had not contain the muscular elements of superficial part external anal sphincter at 80% cases; the wall of apical part of rectum characterized by the hypoplasia of mucous membrane and the muscular layer with the plethora of their vessels in most cases and presence of vegetative intermuscular neuroganglions.