Ultrasound examination at day of triggering is preferred to assess endometrial thickness since it’s a non invasive procedure. It has been found in various studies that thin endometrium is correlated to poor results in cycles of “intracytoplasmic sperm injection”. Nevertheless, the issue that endometrial thickness greater than certain cutoff value association with better ICSI outcome is still controversial and need further deep research work both clinically and experimentally. The goal of the current research is to evaluate the correlation of endometrial thickness evaluated by ultrasound examination to the outcome of ICSI cycles in a sample of Iraqi infertile women. The current cross sectional study included 290 infertile women undergoing ICSI cycles in a single fertility center in Iraq. We retrieved the clinical reports of those women from the archival pool present in this center. The following variables were reported: age of women, infertility duration, body mass index (BMI), type of infertility and thickness of endometrium estimated by ultrasound at day of trigger and result of pregnancy test. At the end of the study, positive pregnancy test was reported in 98 women out of 290 participants making the pregnancy rate at 33.8 %. Type of infertility, duration of infertility, body mass index and age were not significantly associated with pregnancy outcome (p > 0.05). Mean endometrial thickness in those with a pregnancy test that is positive was higher significantly than that of those with pregnancy test that is negative. The analysis of Receiver operating characteristic has been utilized to determine endometrial thickness cutoff value, figure 2 and table 3. The cutoff value was > 9.3 mm with 74.4 % accuracy level. Our study revealed that ultrasound examination at day of trigger of women undergoing ICSI is a valuable mean in determining positive pregnancy outcome by defining the thickness of endometrium and that endometrium thickness greater than 9.3 mm is the best predictor of positive ICSI outcome.