The concentrations of noradrenaline in preovulatory follicular fluid obtained from women undergoing in vitro fertilization were determined by high-performance liquid chromatography with fluorometric detection and compared with those in peripheral plasma obtained concurrently. All of the follicular fluid samples contained noradrenaline at concentrations substantially higher than those in the corresponding plasma samples. A positive correlation was found between noradrenaline levels in follicular fluid and plasma in each woman (n= 11; r= 0.952; p< 0.001). However, there was no significant difference between noradrenaline concentrations in follicular fluid aspirated from follicles with or without an oocyte [mean±SEM, 0.207±0.002 ng/μl for follicular fluid samples with an oocyte (n= 44), and 0.221±0.003 ng/μl for follicular fluid samples without an oocyte (n= 13)]. The data indicate that noradrenaline accumulates in follicular fluid, supporting the physiological significance of noradrenaline in the local regulation of human ovarian functions.