The effect of diminished ovarian reserves after undergoing hysterectomies with bilateral salpingectomies is one of the health concerns among reproductive-age women with benign gynecologic diseases. Coenzyme Q10 (CoQ10), an antioxidant, is crucial in mitochondrial energy production, improving oocyte quality and quantity. This study compares the benefit of a 14-day preoperative (CoQ10) versus placebo on ovarian reserve by measuring anti-mullerian hormone (AMH) in women undergoing hysterectomy with bilateral salpingectomy. A double-blinded, randomised, placebo-controlled trial was conducted. Forty-four women with benign gynecologic diseases were randomised to receive either oral CoQ10 300 mg per day or placebo for 14 days before undergoing hysterectomy with bilateral salpingectomy. Serum AMH levels were collected for analysis before taking CoQ10 and 6 weeks postoperatively in each group. The baseline demographic, clinical characteristics, and baseline AMH levels were comparable between the groups (1.47(0.45,2.49) vs.1.29 (0.47,2.11), p=0.763). The serum AMH levels after the surgery were significantly decreased from pre-operative levels (median 0.99 (0.37,1.63) vs 1.34 (0.57,2.30)), p= 0.001. However, there was no significant difference in the AMH change between the CoQ10 group and the placebo group (AMH per cent change -28.2% (64.09, -4.81) vs -20.07% (-61.51, -2.92)), p= 0.99, respectively. Age, gynecologic disease, operative time, and blood loss were not significantly associated with the AMH change. There were no significant side effects or adverse operative outcomes among coQ10 users. In conclusion, Hysterectomy with bilateral salpingectomy led to a significantly decreased AMH level. However, pretreatment with CoQ10 for two weeks was ineffective in protecting an ovarian reserve.