Polycystic ovary syndrome (PCOS), and nodular and autoimmune thyroid diseases are frequently seen disorders. Previous studies reported conflicting results regarding possible association between PCOS and thyroid disorders. In this study, we investigated the frequency of autoimmune thyroid disease (AITD) and nodular goiter in patients with PCOS. Seventy-three PCOS patients and 60 age-matched controls were enrolled in the study. In PCOS group, body mass index values (27.45 ± 5.73 vs. 22.55 ± 3.78 kg/m(2), p < 0.001, respectively), systolic [110 mmHg (90-130) vs. 100 mmHg (90-140), p = 0.016, respectively] and diastolic (72.67 ± 6.52 vs. 66.42 ± 8.88 mmHg, p < 0.001, respectively) blood pressure, waist circumference (86.27 ± 14.41 vs. 78.78 ± 8.87 cm, p < 0.001, respectively), and homeostasis model assessment-insulin resistance (HOMA-IR) levels (2.96 ± 2.11 and 1.77 ± 0.83 p < 0.001, respectively) were higher than controls. However, thyroid nodule frequency was similar in both groups [22 (30.1 %) vs. 12 (20 %)], also thyroid gland volume was not significantly different [9.23 ml (3.08-32.40) vs. 8.52 ml (4.28-50.29)] among groups. The percentages of patients with thyroid parenchymal heterogeneity, positive anti-thyroid peroxidase, anti-thyroglobulin, and AITD were similar. Cases were reclassified according to the presence of thyroid nodule in which similar HOMA-IR levels were detected (median 2.39 and 1.89, p = 0.093, respectively) despite the fact that the group with nodules had higher mean age (26.5 (18-37) vs. 21 (18-34), p = 0.013, respectively). Similar ratios of thyroid nodule and AITD were found in patients with PCOS and controls.