Transsexualism (ICD-10: F64.0) is congenital condition which manifests as a gender identity disorder and a conflict between biological and self-identified gender. Gender dysphoria associated with transsexualism impairs quality of life, socialization and increases the risk of suicidal behavior. Transsexualism is an acute social and medical problem. Patients demonstrate high number of suicidal attempts without medical assistance. Medical care for this disease is complex and requires a multidisciplinary approach with involvement of psychiatrists, psychologists, plastic surgeons, gynecologists, urologists and endocrinologists. Plastic surgeons are essential at the stage of sex reassignment surgery (SRS) since most stages are performed using plastic and microsurgical methods. Incidence of gender identity disorder is unclear because the most studies focus on the patients seeking for medical assistance or simply counts the number of surgeries performed in different countries. Other studies use different methodology such as social surveys of large groups of cisgender people. In particular, there are studies including anonymous social surveys of large samples of people not associated with transsexualism, studies involving patients in specialized clinics, trials considering the number of gender reassignment surgeries performed in certain hospitals, studies devoted to the number of people who applied for document change. Incidence of transsexualism in Russia is unknown but this work should be continued to improve the quality of medical care provided to transgender people. This article reviews the most recent studies of the incidence of transsexualism.