The aim of this study was to evaluate how, in patients with polycystic ovary syndrome, the number of small subcapsular follicles correlates with uterine and ovarian blood flow and with specific hormonal parameters. At an ultrasonographic evaluation, 30 patients with polycystic ovary syndrome showed 5-10 (group I; n = 14) or > 10 (group II; n = 16) small follicles. These patients underwent ultrasonographic (ovarian volume and stroma echodensity; number, diameter and distribution of follicles) and color Doppler (uterine and intraovarian vessels) analyses, and hormonal assay. In group II, significantly lower pulsatility index values than in group I were observed in the ovarian stromal arteries. The Ferriman-Gallwey score, plasma androstenedione level and luteinizing hormone/follicle stimulating hormone (LH/FSH) ratio results were significantly higher in group II than in group I. Androstenedione plasma levels correlated with the number of small follicles. Furthermore, the LH/FSH ratio correlated with both the number of small follicles and the stromal artery pulsatility index. The combined assessment of ovarian morphology by transvaginal ultrasound and color Doppler may provide insight into the pathological state of polycystic ovary syndrome.