Objectives: This study compared serum anti-Mullerian hormone (AMH) levels in endometriotic cysts (ECs) with those in non-ECs and analyzed changes thereof after single-port laparoscopic (SPL) ovarian cyst enucleation using vasopressin injection. Methods: In total, 180 patients (EC group, n = 112; non-EC group, n = 68) who underwent SPL ovarian cyst enucleation were retrospectively reviewed. Their AMH levels were checked preoperatively, on postoperative day 10 (POD10), and on postoperative month 3 (POM3). Changes in AMH levels were analyzed according to tumor type and vasopressin use. Results: The median initial and postoperative serum AMH levels in the EC group were significantly lower than those in the nonEC group (preoperation: 2.0 vs 3.8 ng/mL, P < 0.001; POD10: 1.0 vs 3.2 ng/mL, P < 0.001; POM3: 1.2 vs 3.6 ng/mL, P < 0.001). The postoperative decrease in AMH levels was higher in the EC group than the non-EC group on POD10 (0.8 vs 0.5 ng/mL, P = 0.011) but not on POM3 (0.7 vs 0.5 ng/mL, P = 0.164). Vasopressin injection during EC enucleation had no significant effect on the decrease in AMH levels on POD10 (vasopressin group vs non-vasopressin group: 1.0 vs 0.8 ng/mL, P = 0.253) and POM3 (vasopressin group vs nonvasopressin group: 1.4 vs 1.1 ng/mL, P = 0.242). Conclusions AMH levels were lower at baseline and had higher decreasing rates after SPL surgery in the EC group relative to the nonEC group. Vasopressin injection might not protect the ovary from the postoperative decrease in AMH levels.