Intra- and interobserver reproducibility of Doppler measurements of the pulsatility index (PI) and time-averaged maximum velocity (TAMXV) in the uterine and ovarian arteries were evaluated in examinations of healthy premenopausal women. Each woman underwent reproducibility measurements once in the late follicular phase and once in the midluteal phase. Intraobserver repeatability was assessed in examinations of 12 women, three replicate Doppler measurements being made by one observer in the same vessel. Interobserver agreement was assessed by comparing the results of Doppler measurements made by two investigators in 11 women. The intraclass correlation coefficient (Intra-CC) was 0.78 for the TAMXV in the dominant uterine artery in the follicular phase and 0.82 for the PI in the wall of the dominant follicle. For all other measurements the Intra-CC was < 0.75, indicating poor reproducibility. The interclass correlation coefficient (Inter-CC) was > 0.75 (0.79 to 0.88) for the PI and TAMXV in the dominant uterine artery in the follicular phase and for the PI of both uterine arteries in the luteal phase. For all other measurements the Inter-CC was < 0.75.