Introduction: The formation of tissue that resembles endometrium outside of the uterus is a hallmark of the chronic
inflammatory disease known as endometriosis. Ovarian endometriosis typically affects women. 19%–28% of endometriosis patients have bilateral ovarian endometriomas. Laparoscopic cyst excision for endometriotic ovarian cysts improves fertility and reduces recurrence. The vasopressin injection approach was developed to reduce endometrioma recurrence and preserve ovarian reserve after laparoscopic cystectomy. Some texts and research recommend vasopressin for laparoscopic ovarian cystectomy.  Material and Methods: This was a study done in Benha University hospital and Aminah Endoscopy Center from January 2021 to February 2022 . The study was conducted on 75 subjects. The study's subjects were women who were scheduled
for laparoscopic surgery and had ovarian endometriomas. 25 patients are the group of non-injected laparoscopic cystectomy made up Group 1 (control group). 25 patients from Group 2 (the saline group) had saline injections and a laparoscopic cystectomy. Group 3 vasopressin injection group (VI group) included 25 patients who had laparoscopic cystectomy with diluted vasopressin injection.  Results: In the VI and saline groups, there were statistically significant differences from the control group in the incidence of ovarian tissue involvement in endometrioma wall specimens, the thickness of tissue specimens, and the thickness of ovarian tissue accidentally removed. However, these alterations did not differ statistically significantly between the VIT and saline groups. Conclusion: Vasopressin injection method decreases the harm that conventional laparoscopic cystectomy causes to ovarian reserve.