The premature rise of progesterone and increase in progesterone/estradiol ratio on the late follicular phase, negatively affect the clinical outcome of fresh embryo transfers in ICSI cycles, a progesterone level above 1.5 ng/ml and P4/E2 ratio above 1 on the day of trigger have different endometrial gene expression profiles, lead to asynchrony between the endometrium and the fresh embryo transfer. The aim is to analyze the relationship between pre ovulatory progesterone rise and increase in progesterone/estradiol ratio on the late follicular phase with clinical pregnancy outcomes of fresh embryo transfers in Intracytoplasmic sperm injection (ICSI). This study done on 120 infertile women selected according to the type of programs used in intra cytoplasmic sperm injection (ICSI) cycles, divided into 60 infertile women stimulated by long agonist protocol and 60 infertile women stimulated by antagonist protocol. Parameters which measured included basal blood sampling and hormones assays in preceding cycles and clinical characteristic of ICSI cycle, on cycle day 2-3, stimulation parameters and on triggering day measured serum progesterone, serum E2, LH by VIDAES and ratio of P4/E2, ultrasound for endometrium thickness (ET) and finally calculated number of oocytes pickup, the maturation rate, fertilization rate, cleavage rate, implantation rate and biochemical and clinical pregnancy rate. (120) infertile women, 35(29.16%) women had positive pregnancy while 85(70.83%) with negative pregnancy. All parameters that measured and clinical characteristics that examined showed no significant difference in the current study except serum progesterone level at trigger day was significantly lower (P=0.010) and the ratio P4/E2 was highly significantly lower (P<0.001) in women who succeed to get pregnant in comparison to women who failed to get pregnant. Total number of embryos was significantly higher (P=0.033) and there was significant increase in mean number of fresh embryo transfer grade 1 (P=0.037) in pregnant women in comparison with women with negative pregnancy. Conclusion: Serum progesterone level and P4/E2 ratio can be used as accurate and sensitive predictors of pregnancy outcome in fresh embryo transferred in ICSI.