Follicular fluid concentrations of growth hormone (GH), insulin-like growth factor-I (IGF-I), epidermal growth factor (EGF) and oestradiol were related to diversities in oocyte maturation and fertilization among oocytes obtained for in-vitro fertilization (IVF). Follicular fluid GH, IGF-I and oestradiol concentrations were significantly correlated with increasing follicular size. Follicles with immature oocytes had concentrations of oestradiol that were significantly lower when compared to follicles with intermediate and mature oocytes. Follicular fluid EGF concentration was similar for all oocyte maturational stages. In follicular fluids with mature oocytes we found IGF-I and GH concentrations were significantly higher compared to those of follicular fluid with atretic oocytes. Follicular fluids with immature and intermediate oocytes had similar concentrations of GH and IGF-I to follicular fluid containing mature oocytes and higher concentrations than follicular fluid with atretic oocytes. No statistically significant difference was found between fertilized and unfertilized oocytes. We conclude that maturation of oocytes is associated with higher concentrations of GH, IGF-I and oestradiol, but follicular fluid IGF-I and GH concentrations cannot serve as a predictor for IVF.