Abstract The aim of the study: to evaluate correlation between androgen and 17-hydroksyprogetserone concentrations in blood serum and menstrual patterns of women with polycystic ovary syndrome. Material and methods: 227 patients with polycystic ovarian syndrome (PCOS), aged 18 to 35 years, hospitalized at the Department of Gynecological Endocrinology. All patients with PCOS presented clinical and biochemical evidence of hiperandrogenism with oligoovulation and/or ultrasonographic appearance of polycystic ovaries. PCOS was diagnosed according to the Rotterdam Criteria after excluding reasons such as: congenital adrenal hiperplasia, adrenal and ovarian tumors, hiperprolactinemia and hypo- hiperthyreosis. The following hormone concentrations were measured in each patient: total testosterone (TT), androstendione (A), dehydroepiandrosterone sulphate (DHEAS) and 17-hydroxyprogesterone (17-OHP). The patients were divided into 4 groups: I – eumenorrhoeic (n=66), II – polymenorrhoeic (n=32), III – oligomenorrhoeic (n=93), IV – with secondary amenorrhea (n=36). The control group consisted of 40 patients with normal regular menstrual cycles and no clinical/biochemical sings of hiperandrogenism. Statistical analysis was performed using one-way Anova and NIR test. P<0,05 were considered to be statistically significant. Results: The mean TT concentrations were as follows: Group I - 0.91± 0.56 ng/ml, II -0.91±0.22, III – 0.91±0.48, IV – 1.66±1.78ng/ml; Androstendione: I – 3.34±1.32, II – 2.77±0.75ng/ml, III – 3.28±1.00ng/ml, IV – 4.29±2.18ng/ml, 17-OHP: I – 1.08±1.61ng/ml, II – 0.89±0.62ng/ml, III – 0.94±0.37ng/ml; IV – 1.68±1.28ng/ml and DHEAS: I – 5.69±2.49μmol/l, II – 6.11±3.11μmol/l, III – 6.04±3.00μmol/l, IV – 6.12±3.25μmol/l respectively. The hormone concentrations in the control group were as follows: TT – 0.58±0.35ng/ml, A – 2.33±0.52ng/ml, 17-OHP – 0.67±0.30ng/ml, DHEAS – 5.24±2.33μmol/l. We found significantly higher TT, A, 17-OHP concentrations in all PCOS subgroups than in the healthy subjects (p<0.05). The PCOS group analysis revealed that all the mentioned hormone concentrations were significantly higher in women with secondary amenorrhea (group IV) than in the remaining 3 groups (p<0.05). We found no significant difference in DHEAS concentrations between the study and the control group. Conclusions: Higher total testosterone, androstendione and 17-hydroksyprogesterone concentrations, longer menstrual cycles in women with PCOS.