This advanced laparoscopic surgery video demonstrates fertility-preserving cystectomy for a 6 cm ovarian endometrioma in a 28-year-old woman with infertility concerns. The surgeon illustrates careful adhesiolysis, assessment of ureteric anatomy, controlled drainage of the endometrioma, and a novel inside-out cystectomy technique using vasopressin hydrodissection. The endometrioma capsule is peeled away from the ovarian cortex with minimal traction and almost no thermal energy, maximizing preservation of ovarian reserve. The ovary is then reconstructed with intracorporeal suturing, and the specimen is retrieved safely in an Endobag. An incidental finding of deep infiltrating endometriosis is discussed, along with the rationale for deferring bowel surgery due to the absence of informed consent and multidisciplinary planning. This is an excellent educational video for gynecologic laparoscopic surgeons focused on fertility-preserving endometriosis surgery.