Objectives: To assess variability and predictability of adiponectin, leptin, resistin and their ratios in non-obese and obese women with anovulatory polycystic ovary syndrome (aPCOS). Results: A total of 52 ovulatory controls (mean age=31.63±4.88 years, BMI=25.33±2.68 kg/m3); 54 non-obese [mean age=32.11±4.25 years, BMI=25.72±2.95 kg/m3] and 50 obese women with aPCOS [mean age= 33.64±4.14 years, BMI=39.19±2.99 kg/m3] were recruited. The aPCOS group had lower adiponectin [13.0(10.49-16.59) vs 18.42(15.72-19.92) µg/ml, p<0.0001], adiponectin: leptin ratio (A:L) [0.60(0.35-0.88) vs 1.19(0.92-1.37), p<0.0001], and adiponectin: resistin ratio (A:R) [0.30(0.21-0.43) vs 0.42(0.32-0.62), p<0.0001] but a higher leptin [20.02(14.54-26.80) vs 16.17(14.51-18.36) ng/ml, p<0.0001] and leptin: resistin ratio (L:R) [0.53(0.37-0.82) vs 0.40(0.27-0.48), p<0.0001] compared to the controls. The obese aPCOS group had lower adiponectin [11.04(5.66-13.25) vs 14.18(11.04-18.02), p<0.0001 and 18.42(15.72-19.92) µg/ml, p<0.0001], A:L [0.36(0.27-0.44) vs 0.78(0.61-1.16), p<0.0001 and 1.19(0.92-1.37), p<0.0001], and A:R [0.24(0.17-0.38) vs 0.40(0.23-0.58), p<0.0001 and 0.42(0.32-0.62), p<0.0001] but a higher leptin [26.80(14.28-32.09) vs 17.95(14.86-21.26), p<0.05 and 16.17(14.51-18.36) ng/ml, p<0.0001] and L:R [0.63(0.46-1.03) vs 0.41(0.30-0.61), p<0.0001 and 0.40(0.27-0.48), p<0.0001] compared to the non-obese aPCOS and control group, respectively. A:L showed the best discriminatory power in predicting aPCOS (AUC=0.83), followed by adiponectin alone (AUC=0.79), L:R and leptin alone (both AUC=0.69). Resistin alone had the poorest discriminatory power (AUC=0.48).