['To investigate changes in serum anti-Müllerian hormone (AMH) concentrations following ovarian cyst surgery, and predictors of these changes.', 'Prospective cohort study with follow up at 3 and 6\xa0months.', 'University hospital.', 'Women of reproductive age scheduled for ovarian cyst surgery.', 'Women were recruited between March 2011 and March 2012 (n\xa0=\xa075). Serum AMH concentrations were measured preoperatively and at 3 and 6\xa0months postoperatively.', 'Changes in AMH after surgery and predictors for these changes.', "After surgery, median AMH levels decreased significantly from 2.7\xa0μg/L (0.2-16.9) to 1.6\xa0μg/L (0.2-9.9) at 3\xa0months and were still low, 1.6\xa0μg/L (0.2-8.3) at 6\xa0months (both p\xa0<\xa00.001). In patients with unilateral cysts, a significant and more rapid AMH decrease was seen after enucleation of endometriomas (n\xa0=\xa019) vs. dermoid cysts (n\xa0=\xa022) (p\xa0=\xa00.010). The reduction was long-lasting at 6\xa0months. In a multivariate regression analysis, a higher baseline AMH concentration was predictive of AMH reduction at 3 [odds ratio (OR) 1.9, 95% CI 1.1-3.1] and 6\xa0months postoperatively (OR 2.5, 95% CI 1.2-5.2). Women with normal or elevated baseline AMH presented with a significant reduction of -23% and -43% at 3 and 6\xa0months, respectively, whereas women with low or very low AMH had minimal or no changes over time. Patient's age, cyst size, duration of surgery or intraoperative bleeding were not predictive of a postoperative AMH decrease."] Is anti-Müllerian hormone reduction after ovarian cyst surgery dependent on the histological cyst type and preoperative anti-Müllerian hormone levels?