In this thesis, the new International Guidelines for the Assessment and Treatment of Polycystic Ovary Syndrome (PCOS), published in 2023, are presented. PCOS is the most common endocrine and metabolic disorder in women of reproductive age. It is defined by the presence of at least two of the following three criteria: 1. Oligo-ovulation or anovulation; 2. Hyperandrogenism; and 3. Polycystic ovarian morphology on ultrasound, which is characterized by the presence of 12 or more follicles in each ovary measuring 2-9 mm in diameter and/or increased ovarian volume (>10 ml). It is important to note that the diagnosis of PCOS is made by excluding other causes of hyperandrogenism and anovulation, such as congenital adrenal hyperplasia, Cushing's syndrome, or androgen-secreting tumors. The guidelines emphasize the importance of an individualized approach in the diagnosis and treatment of PCOS, taking into account the specific symptoms and needs of each patient. The cause of polycystic ovary syndrome is not fully understood, but it is thought to result from a combination of genetic and environmental factors. Women with PCOS have an increased risk of developing infertility, glucose intolerance, type 2 diabetes, dyslipidemia, hypertension, cardiovascular diseases and endometrial cancer. There is also an increased prevalence of depressive symptoms and anxiety, including low self-esteem, eating disorders, and psychosexual dysfunction. Considering the diversity and number of its manifestations, this syndrome should be taken seriously, and its treatment should be consistent, individualized, and tailored to the needs of each patient. With the development of new insights in PCOS, old guidelines are being revised, and new ones provide the possibility of better control of the symptoms and health consequences of this syndrome.