Background: Irisin is a recently identified myokine that acts like adipokines. It has been revealed to be connected with insulin resistance (IR), obesity, and metabolic syndrome. Objective: To investigate serum, follicular fluid (FF), irisin, and IR in lean, overweight, and obese women undergoing the intracytoplasmic sperm injection (ICSI) cycle and correlate them with oocyte and embryo quality. Methods: Ninety infertile Iraqi women aged 18 to 40 years had primary or secondary infertility. They were enrolled in this study and divided into three groups according to body mass index ranking: the first group: twenty-seven normal-weight females, the second group: thirty-five overweight females, and the third group: twenty-eight obese females. ICSI was done for them to evaluate the level of serum and follicular fluid Irisin with the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) at the day of oocyte pickup and correlate them to the outcome. Results: HOMI-IR, serum, and FF Irisin levels were significantly higher in obese people. Also, there was a significant difference between groups in regard to MII, oocyte maturity rate, grade 1 embryo, and pregnancy outcome, which was less in the obese group. In addition, there was a significant negative correlation between HOMI-IR and irisin levels in serum and follicular fluid with MII oocyte count, oocyte maturity rate, embryo grade 1, and pregnancy outcome. Conclusion: Serum, follicular fluid Irisin, and HOMA-IR were significantly higher in obese cases than in lean cases, which may cause a reduction in the ICSI outcome.