Abstract The outcomes of laparoscopic cystectomy of endometri- omas have been the subject of numerous investigations. Endometriosis is the term used when endometrial glands and stroma are seen outside of the usual uterine cavity. Ectopic endometrial tissue growing inside the ovary leads to pseudocysts known as endometriomas. The best course of treatment for women with symptomatic or expanding endometriomas is first surgery. Analyzing the serum level of antimullerian hormone (AMH) can be used to estimate ovarian reserve. This study's objective was to evaluate how laparoscopic ovarian cystectomy for endometrioma affected ovarian re- serve. Methods: This prospective interventional study on96 pa- tients of ovarian endometriomas candidate for laparoscopic ovarian cystectomy. All patients included in the study were subjected to; de- tailed history taking and full examination, day 3Follicular Stimulating hormone (FSH) and Antimullerian hormone (AMH)measurement the cycle before operation then sub- jected to laparoscopic cystectomy and histological exam- ination then the same tests were repeated on day 3 of the cycle three months postoperative. Results: There was a statistically significant reduction in postoperative mean value of AMH (2.04+ 1.69) when com- pared to the preoperative mean value of AMH (2.59+ 1.85) and a statistically significant rise in postoperative mean val- ue of serum FSH (7.23+ 1.48), when compared to preopera- tive mean value of FSH (5.50+ 1.85). In this study, patients with endometriomas> 5 cm in diam- eter compared to smaller ones saw larger post-operative AMH declines (p value 0.001 and 0.01 respectively), as well as those with bilateral endometriomas compared to those with unilateral ones. (p value <0.001, 0.02 respectively), so endometrioma size and bilaterality of endometriomas were significant risk factors for diminished ovarian reserve. Conclusion: Laparoscopic cystectomy of endometrioma has an adverse effect on ovarian reserve reflected by Antimullerian hormone that decreases significantly after Laparoscopic ovarian cystectomy and FSH level that increases significantly after Laparo- scopic ovarian cystectomy.