Endometriosis affects up to one in ten women of reproductive age and often goes unrecognized and undertreated.[1][4] It is a chronic inflammatory disease that has a great impact on the quality of life of affected women.[1] The main symptoms include very painful menstruation, painful intercourse and fertility disorders.[1][3] It is characterized by the ectopic appearance of the endometrium and has a negative effect on female fertility.[3] In 2026, the ICD-10-CZ is updated with a significant revision of the coding of endometriosis (N80), which introduces five-digit sub-items for a more precise description of location, extent and severity.[7] The new codes allow more detailed clinical use of data and include a separate item N80.7 for endometriosis of the urinary system.[7]