The view of the clinical picture of primary hyperparathyroidism (PHPT) has essentially changed during the recent years under the influence of new data about its prevalence and the structure of the disease. The analysis of the database created at the Endocrinological Research Centre and including 1053 patients was used to obtain an epidemiological characteristics of various forms of PHPT recorded in Russia. PHPT morbidity in Moscow was estimated, based on the incidence of outpatient visits, to reach 0.05 per 1,000 adult population. This figure is significantly lower than that reported in foreign publications. The manifest form appears to be the most widespread form of PHTP in this country. The relative prevalence of the mild form has increased in the last years (till 2012) but does not exceed 28% or significantly lower than abroad where it is reported to prevail in the structure of PHPT morbidity. The asymptotic form accounts for 7.5% of all PHPT cases in the framework of type 1 multiple endocrine neoplasia syndrome (MEN-1) where it most frequently occurs in combination with pituitary adenomas (81%), in the first place prolactinomas, somatotropinomas, and pancreatic tumours (45%).