The purpose of this publication is to show and analyse the issue of transsexual people who feel the need to reassign their sex assigned at birth and their biological sex due to a gender identity disorder. The paper is a polemic against the views presented in the case-law practice, suggesting the uniform and statutory regulation of transgender people’s situation in Polish law, drawing from the achievement of the ‘Principles’ written in Yogyakarta. One of the main postulates resulting from this publication concerns the regulation of the conditions and procedure of the legal sex transition that guarantee transsexual people the enjoyment of their fundamental rights and freedoms on equal terms with other members of society. The article is supposed to contribute to combating discrimination and increasing awareness in the area of transsexuality which is viewed stereotypically and is unknown to most people, with the exception of a small group of experts who fight against exclusion that conditioned by a different gender identity.