Objectives: The aim of this study is to evaluate the association between changes in C reactive protein and pregnancy rate in IVF/ICSI. Patients and methods: A prospective cohort study that was conducted in Ain Shams University Maternity Hospital, Infertility Clinic during period time from September 2018 to September 2020. A total of 100 infertile women who were candidate for IVF/ICSI, over a period of 2 years, beginning in September 2018 were recruited to the study after they met the inclusion and exclusion criteria. The participants gave written informed consent and approval for the ethical aspects of the study. Results: This study showed no statistically significant differences according to clinical pregnancy regarding the sociodemographic data as BMI, duration of infertility and type of infertility and regarding Oocyte retrieval and embryo transfer, also no significant differences according to clinical pregnancy regarding CRP at baseline and at Oocyte pickup as well as CRP change at oocyte pickup. But age was significantly lower in cases with clinical pregnancy and CRP at embryo transfer and CRP change at embryo transfer were significantly higher in cases with positive pregnancy. Conclusion: Finally, we concluded that patients whose CRP level decreased on transfer day, had lower chance of pregnancy, whereas patients whose CRP level elevated on embryo transfer day had high chance of pregnancy