Diminished ovarian reserve (DOR) is a disorder characterized by impaired ovarian function. Sleep disorders are disruptions of the circadian rhythm, which appears to be closely linked to reproductive systems. This study aimed to investigate the impact of poor sleep quality on the ovarian reserve of childbearing-age women.A cross-sectional study was conducted in China from June 2021 to March 2023. In total, 102 participants diagnosed with chronic insomnia disorder were included in the study. Questionnaires were administered to assess participants' menstrual patterns, insomnia severity, anxiety, and depression. The anti-Müllerian hormone level and the basal antral follicle count were measured for ovarian reserve evaluation. Correlation analysis and ordinal logistic regression analysis were conducted.The women with insomnia presented high percentages of hypomenorrhea, premenstrual syndrome, and dysmenorrhea (78.4%, 74.5%, and 46.1%, respectively). Severe sleep disorder in the past month was identified as an independent risk factor for hypomenorrhea and premenstrual syndrome (odds ratio [OR], 2.64 and OR, 2.688; p<0.05). The prevalence of DOR among women with insomnia (33.3%) was significantly higher than the average reported in previous studies for young women. Insomnia duration exceeding 1 year was determined to be an independent risk factor for DOR in women aged 36 to 40 years (OR, 4.5; p=0.033).This study highlights the association between sleep disorders and menstrual problems. Prolonged poor sleep quality in women aged 36 to 40 years was identified as a significant risk factor for DOR. We should pay more attention to improving sleep quality in order to maintain normal ovarian function.