Objectives: The objective of this study was to evaluate the impact of luteinizing hormone (LH), estradiol (E₂) and progesterone (P) levels on the day of human chorionic gonadotropin (HCG) administration on outcomes of in vitro fertilization (IVF) in controlled ovarian hyperstimulation (COH). Study Design: In this retrospective study, 129 infertile women undergoing IVF / intracytoplasmic sperm injection (ICSI) treatments were included; these cycles were stratified according to LH levels of ≥ 1.12 IU/L or < 1.12 U/L and according to E₂ levels of ≥ 1,005.89 pmol/L or < 1,005.89 pmol/L. The main outcome measure was the clinical pregnancy rate. Results: The clinical pregnancy rate was significantly higher in the group with LH ≥ 1.12 IU/L than in the group with LH < 1.12 U/L (43.28% vs. 30.65%, p < 0.05). The clinical pregnancy rate was also higher in the group with E₂ ≥ 1,005.89 pmol/L than in the group with average E₂ < 1,005.89 pmol/L (42.86% vs. 30.51%, p < 0.05). Among the LH, E₂, and P levels on the day of HCG administration, LH level was the most important predictor of outcomes of IVF in COH. The present data showed an adverse effect of low serum LH level (LH < 1.12 IU/L) on the day of HCG administration on clinical pregnancy rate. E₂ level can also predict the outcomes of IVF in COH. Conclusions: Low serum LH level (LH < 1.12 IU/L) and low serum E₂ level (average E₂ < 1,005.89 pmol/L) on the day of HCG administration led to low clinical pregnancy rates, while the P level on the day of HCG administration may have had little effect on clinical pregnancy.