Aim: to determine the incidence and association of thyroid dysfunction in patients with Abnormal Uterine Bleeding. Materials and Methods: The present analytical cross-sectional clinical study was conducted in the Department of Obstetrics and Gynecology, Darbhanga Medical College and Hospital, Bihar. 130 patients with abnormal uterine bleeding of were found to be eligible for inclusion in the study. Results: Mean age of the study subjects was 33.04 years. Majority of patients was multiparous (56.9%). 43.8% of women presented with complaint of heavy menstrual bleeding were having thyroid dysfunction. Conclusion: Abnormal uterine bleeding found strongly associated with thyroid related disorders. Hence the evaluation of thyroid function forms an essential component among abnormal uterine bleeding patients.