Recent studies have proposed that, in women affected by the polycystic ovary syndrome (PCOS), aging is able to regularize the menstrual cyclicity. To evaluate the ovarian response in PCOS patients according to their age, we studied 33 PCOS patients, 20 of whom with an age ranging from 28 to 34 years (younger PCOS) and 13 ranging from 35 to 45 years (older PCOS). All patients underwent an ovulation induction therapeutic protocol with low-dose recombinant follicle stimulating hormone, for a total of 80 cycles (44 cycles for the younger PCOS group and 36 cycles for the older PCOS group). No significant difference was found between the days of therapy (12.3 +/- 5.4 vs. 13.5 +/- 5.6 days), total amount of drugs (980.7 +/- 568.9 IU vs. 1063.9 +/- 469.5 IU) or ovulation rate (93% vs. 89%) in the two groups. The two groups showed a significant difference in the maximum estradiol level (2053.5 +/- 1497.2 vs. 1269.0 +/- 911.5 pmol/l, p < 0.01), the number of the recruited and preovulatory follicles (1.7 +/- 2.5 vs. 0.64 +/- 0.9, p < 0.05 and 1.7 +/- 1.1 vs. 1.2 +/- 0.5, p < 0.01, respectively) and the pregnancy rate (36% vs. 14%, p < 0.05). In conclusion, our data clearly showed that, also in PCOS, advanced age is a negative prognostic factor in the ovarian response to ovulation induction therapies.