Observations of several clinical variants of poroceratosis are presented. Genetic factors with autosomal dominant type of inheritance and environmental factors, including the intensity of insolation, concomitant diseases, drug-induced immunosuppression, contributing to its occurrence, are described. According to the modern classification, localized and disseminated forms are distinguished. Localized ones include porokeratosis of Mibelli, linear porokeratosis, palmar-plantar punctate, genital, perianal porokeratosis; disseminated ones are superficial actinic, superficial disseminated, disseminated palmar-plantar, systematized linear porokeratosis. The variety of porokeratosis forms along with the identity of histological signs allows to consider them to be a clinical variants of one disease. Methods of treatment include both external therapy — cytostatic drugs, vitamin D3 analogues, immunomodulators, calcineurin inhibitors, retinoids, and systemic — retinoids, as well as surgical excision of foci, cryotherapy, electrodissection and curettage of formations, dermabrasion of foci and photodynamic therapy. In addition, patients should be informed about the use of sunscreen and emollients. The choice of treatment option is determined by the form of the disease, localization, prognosis, and cosmetic indications. Timely diagnosis and monitoring of patients suffering from porokeratosis (especially linear form), and persons with immunosuppression, is important because the risk of squamous cell carcinoma of the skin in the foci in such patients is elevated.