Objective: To investigate the correlation between concentrations of growth differentiation factor (GDF)-9 in single follicular fluid (FF) and the corresponding oocyte developmental competence. Methods: Forty-eight infertile women participating in vitro fertilization procedure between March 2007 and July 2009 were recruited when at least one mature oocyte was obtained and the corresponding FF from single follicle was available. Patients were stimulated with recombinant follicle stimulating hormone and the pituitary was suppressed by gonadotropin- releasing hormone agonist long or antagonist protocol. The levels of GDF-9 were estimated by a sandwich enzyme-linked immunosorbent assay using commercial monoclonal antibody. Results: The median concentration of FF GDF-9 did not differ according to occurrence of fertilization (7.4 vs. 1.9 ng/mL, P=0.665). By using receiver operating characteristic curve analysis, level of FF GDF9 could not predict the occurrence of fertilization or the formation of good-quality embryo. The concentration of FF GDF9 was not correlated with the matched embryo score. Conclusion: Level of FF GDF9 might not be clinically useful to predict oocyte developmental competence.