ABSTRACT Objective To compare serum anti-Müllerian hormone (AMH) and other endocrine parameters between patients diagnosed with polycystic ovary syndrome (PCOS) and age-matched ovulatory women. Materials and methods AMH, DHEAS, FSH, LH, PRL, TSH and total testosterone (TT) were prospectively measured in oligo-ovulatory PCOS patients (n = 595) and in ovulatory non-PCOS women (n = 157) referred to a tertiary infertility center. Mean BMI was similar across the two study populations and there were no smokers in the sample. Patients in both groups were further classified into three categories by age: < 25 yrs, 25-34 yrs, and ≥ 35 yrs. Selected clinical and demographic characteristics were tabulated for each group. Results Serum AMH was significantly higher among PCOS patients compared to non-PCOS controls in the non-stratified sample (7.54 ± 5.8 vs. 2.49 ± 2.0 ng/mL, respectively; p < 0.0001), while serum FSH, DHEAS, TSH and prolactin were similar for both groups (p > 0.05). As expected, mean (total) testosterone levels were notably different between PCOS vs. non-PCOS controls (0.84 ± 0.76 vs. 0.43 ± 0.38 ng/mL, respectively; p < 0.001), and mean AMH level was significantly lower in the oldest age category (> 35 yrs) compared to both younger control groups (p < 0.0001). Both DHEAS and total testosterone decreased with age among PCOS patients, although mean serum DHEAS for women age > 35 yrs was significantly lower than DHEAS measured in younger women with PCOS (p < 0.02). For PCOS patients, AMH remained relatively stable irrespective of age. Conclusion Although AMH can serve as a satisfactory marker of ovarian reserve, for PCOS patients the expected decline in AMH associated with reproductive aging appears attenuated despite ovarian senescence. In contrast, mean DHEAS levels were markedly lower among older PCOS women (> 35 yrs) compared to younger PCOS patients.