Résumé : Objective: To analyze the impact of seropositivity with hepatitis C virus (HCV) on in vitro fertilization (IVF) outcomes. Design: Retrospective, case-controlled study. Setting: Fertility clinic of academic hospital. Patient(s): 42 IVF/intracytoplasmic sperm injection cycles in HCV-seropositive women and 84 matched control cycles. Intervention(s): IVF/intracytoplasmic sperm injection treatment for infertility. Main Outcome Measure(s): Ovarian response to stimulation, laboratory findings, and implantation and pregnancy rates. Result(s): Absence of ovarian response was statistically significantly higher for HCV-seropositive women compared with controls (10/42 vs 5/84 cycles, respectively). For cycles with oocyte retrieval, HCV-seropositive women required more gonadotropin units compared with controls. The maximum estradiol levels and number of collected oocytes were similar, but HCV-seropositive women had statistically significantly fewer embryos available compared with controls. Embryo morphologic features, number of transferred embryos, and rates of implantation and pregnancy were similar for HCV-seropositive women and controls. Conclusion(s): When compared with matched uninfected controls, HCV-seropositive women display a decreased ovarian response. © 2007 American Society for Reproductive Medicine.