This review presents the main extraintestinal manifestations (EIMs) in patients with inflammatory bowel diseases (IBD), in particular ulcerative colitis (UC) and Crohn’s disease (CD), describes the modern potential mechanisms, classification, characteristics and frequency of the main EIMs (rheumatological, skin, ophthalmological and orofacial manifestations). The issues of the mechanism of action, indications for prescribing ustekinumab are also covered in detail, the place of ustekinumab in the treatment of IBD is highlighted, the effectiveness of this drug in relation to the treatment of IBD is assessed – summarizes the results of a retrospective analysis of data from the UNITI-1, UNITI-2, IM-UNITI clinical trial program, prospective cohort studies, retrospective cohort studies and a registry study on the effect of ustekinumab on the course of various EIMs and the outcomes of immune-mediated diseases (IMDs) in patients with CD and UC. Ustekinumab is a fully monoclonal human immunoglobulin G1k that binds to the common p40 subunit of interleukin (IL)-12 and IL-23, which are actively involved not only in the development of intestinal symptoms, but are also triggers in the development of various EIMs. A review of the literature showed that ustekinumab may be effective for the treatment of EIMs in patients with UC and CD, especially in relation to dermatological and rheumatological manifestations, and is effective against psoriasis and psoriatic arthritis. A literature search of MEDLINE®, EMBASE®, BIOSIS Previews® and DERWENT® and/or other resources, including internal/external databases was conducted on April 15, 2024.