Objective <p>This study aimed to investigate the relationship between body composition parameters and serum irisin and FABP4 levels in adolescent girls with polycystic ovary syndrome (PCOS).</p> Methods <p>A total of 123 participants (54 with PCOS and 69 controls) were included in this cross-sectional study. Biochemical and hormonal parameters were assessed, and body composition was evaluated using bioelectrical impedance analysis (BIA). Multivariable logistic regression analysis was performed to identify factors associated with PCOS.</p> Results <p>Compared with controls, the PCOS group showed significantly higher levels of total testosterone and luteinizing hormone. Muscle mass index was also higher in the PCOS group, whereas other body composition parameters did not differ significantly between groups. In multivariable logistic regression analysis, total testosterone and Luteinizing hormone emerged as independent predictor of PCOS (OR = 1.089, 95% CI: 1.050–1.128, <i>p</i> &lt; 0.001), (OR = 1.084, 95% CI: 1.003–1.172, <i>p</i> = 0.041) relatively. While BMI Serum irisin and FABP4 was not independently associated with PCOS.</p> Conclusion <p>In adolescent PCOS, hyperandrogenemia, particularly total testosterone, remains the strongest independent correlate of disease status. In contrast, circulating irisin and FABP4 do not appear to provide additional independent discriminatory value. These findings should be interpreted within the limitations of a cross-sectional design, and further prospective studies are warranted.</p> Clinical trial number <p>Not applicable.</p>