Background We previously reported that Glutathione S-transferase theta 1 (GSTT1) was highly up-regulated in aged human ovarian granulosa cells, suggesting that GSTTI may be a biomarker for oocyte quality in age-related infertility.The purpose of this study was to investigate the correlations between the expression of GSTT1 in granulosa cells and the IVF outcomes.Methods Granulosa cells were obtained from seventy-two infertility women who underwent in vitro fertilization-embryo transfer (IVF-ET) between August and December 2012.Total RNA was isolated from mural granulosa cells, and the expression level ofGSTT1 gene was analyzed by the real-time RT-PCR.The Correlations between the expression level of GSTT1 and IVF outcome was examined.Results The patients were separated into two groups according to the expression level of GSTT1.When compared to low GSTTI expression group, the ratio of mature oocytes (MII) and fertilization were significantly lower in the high GSTT1 expression group (p < 0.05).Conclusions: High expression level of GSTT1 in human mural granulosa cells was related to the lower ratio of mature oocytes and fertilization.GSTTI may be a novel candidate marker for indicating the outcomes of IVF.