OBJECTIVE Previous studies suggest that follicular fluid leptin levels predict successful assisted reproduction. The relationship between intrafollicular leptin and the soluble leptin receptor, ovarian hormones, and oocyte quality was examined to determine potential factors contributing to this finding. METHODS Follicular fluid leptin, soluble leptin receptor, hormones, and oocyte quality were examined in 84 individual follicles from 30 women undergoing in vitro fertilization. RESULTS Follicular fluid leptin and soluble leptin receptor levels correlated inversely with each other (r = -0.354; p = 0.001). Follicular fluid leptin levels correlated with intrafollicular estradiol (r = 0.42; p < 0.001), progesterone (r = 0.48; p < 0.001), and androstenedione (r = 0.49; p < 0.001), whereas soluble leptin receptor levels correlated with activin (r = 0.38; p < 0.001) and follistatin (r = 0.35; p < 0.002). There was no relationship between follicular fluid leptin or soluble leptin receptor levels and pretreatment serum hormone levels, stimulated serum estradiol, follicle number, oocyte quality, fertilization, or embryo grade. CONCLUSIONS The data demonstrate that leptin and the soluble leptin receptor are highly interrelated with each other and with other intrafollicular hormones, but not with markers of oocyte quality, fertilization, or embryo grade.