Erythroplasia of Queyrat (EQ) (syn.: papillary epithelioma) is a squamous cell carcinoma in situ of the mucous membranes and the epithelial transition zones. EQ most often develops in males aged 60—80 years with unremoved foreskin and occurs on the balanus and the inner layer of the foreskin. It can occur on the vulva, anogenital area, and oral mucosa. The article provides the overview of the clinical presentation, etiology, pathogenesis, diagnosis, and treatment of EQ. The authors draw attention to the efficacy of photodynamic therapy (PDT) using photosensitizers in treatment of EQ patients. We provide the data of our own clinical observations of successful PDT using methyl aminolevulinic acid (MALA) in the form of 16% cream Metvix as a topical photosensitizer. Aktilite lamp was used as the light source (intense pulsed light (IPL), cold visible red light with the average wavelength of 630 nm and a fluence dose of 37 J/cm2). Complete regression of EQ 3 months after the full course of MALA-PDT, which consists of two procedures, was observed.