Helminthiases are found in the group of the most common and socially significant human infectious diseases. According to current data, at least 1 billion people are infected with helminths or pathogenic infections. One of the most important and widespread human biohelminth parasites in the Russian Federation is the broad-spectrum tapeworm (Diphyllobothrium latum). The absence of specific clinical diagnosis, as well as the predominance of latent forms, determines the presence of diphyllobothriasis disease. The aim of the study was to summarize current data on the epidemiology, pathogenesis, clinical and laboratory manifestations and therapy of diphyllobothriasis. Materials and methods. Clinical cases of diphyllobothriasis were analyzed among patients who were treated in January to November 2022 in the departments of the daytime period of clinical observation of the infectious diseases hospital named after S.P. Botkin, as well as the department of incidents detected and the clinical diagnostic center of Pediatric Research and Clinical Center for Infectious Diseases. Cases of the use of diseases, data from laboratory and instrumental studies, and therapy were evaluated. The most informative of them is given as a clinical example. The article also describes in detail the current biological and epidemiological features of Diphyllobothrium latum, the characteristic clinical picture of diseases and the most frequent complications. Results. Diphyllobothriasis still remains one of the most vulnerable biohelminthiases in Russia, typical for some patients of different ages. Verification of the diagnosis of “diphyllobothriasis” can be of the nature of an “accidental finding” during screening scatological or instrumental studies; upon admission, patients themselves begin to suspect helminthiasis when fragments of the strobila worm are found in the feces. To identify a conditional diagnosis of the pattern of clinical and laboratory infection (exclusion of a complicated course of diseases, helminthiases of a different etiology) and to determine risk factors for the transmission of diseases for the prevention of infections.