Nowadays, an urgent problem of pediatric gastroenterology is the study of inflammatory bowel diseases with very early onset (VEO-IBD), which have unique genetic, clinical, immunological, morphological, and laboratory sings. Early VEO-IBD is usually considered as monogenic disease, especially in combination with congenital immune defects, which leads to difficulties in diagnosis and management this pathology. Despite this, systematization of information about this group of nosological forms of IBD is practically not carried out. This article presents a review of the available information on etiological factors, course variants, and therapeutic options for VEO-IBD.