Polycystic Ovarian Syndrome (PCOS) is introduced as the most common cause for ovarian malfunction, endocrine and metabolic disorder, and result in infertility. PCOS has a noticeable prevalence and affect 5 to 10 % of women in reproductive age, which make it necessary to define some high-accuracy criteria to exact diagnosis of patients. In 1990 National Institutes of Health Criteria (NIH) was defined, then the Rotterdam Criteria was defined in 2003, later The European Society of Human Reproduction and Embryology/American Society for Reproductive Medicine Rotterdam consensus (ESHRE/ASRM) enhanced PCOS diagnosis, and eventually PCOS is defined as hyperandrogenism with ovarian dysfunction or polycystic ovaries by the Androgen Excess Society. Most of the time PCOS is characterized by hyperandrogenism and ovulatory dysfunction but it could have some other manifestations such as oligo-ovulation, insulin resistance, obesity, or sometimes hirsutism. PCO syndrome is described as a multi-factorial disease which could have the environmental and genetic reasons and its pathogenesis is still unknown. According to this matter, clinical signs and symptoms of PCOS could be various. One of the most important issues to notice, is the overlap between adolescence physiological findings which are observed during the normal progression of puberty. It makes the diagnosis process more complicated. It is clear that earlier treatment and even prevention of PCO-associated morbidity is dependent on early diagnosis in adolescent age group, but it should be noticed that premature diagnosis carries risks of psychological distress and unnecessary treatment. An increased risk for developing other disorders, such as adulthood infertility, diabetes mellitus, obstructive sleep apnea, and metabolic syndrome threaten adolescents with PCOS. All of these issues present PCOS as a high noticeable disorder which requires most exact studies.