Background: Abnormal uterine bleeding is an abnormal bleeding from the uterus in absence of organic disease of genital tract. AUB accounts for 10% of all gynaecology related complaints. Thyroid dysfunction by large number is associated with menstrual disorders. Objective: To study thyroid dysfunction in patients with a provisional diagnosis of AUB of all age groups and refer positive cases to physician for further evaluation. Methods: Clinically diagnosed cases of AUB were enrolled from gynaecology OPD of a tertiary hospital. All patients from puberty to premenopausal age groups presenting as menorrhagia, polymenorrhagia, oligomenorrhoea, polymenorrhoea and metrorrhagia were subjected to the thyroid function i.e. T3, T4, and TSH. All data was compiled and analysed. Results: A total of 101 patients were studied. 22.77% of these patients had thyroid dysfunction of which 13% of patients had hypothyroidism, 8% of patients had subclinical hypothyroidism and only 2% of patients had hyperthyroidism. The commonest bleeding abnormality in hypothyroid patients were polymenorrhoea and menorrhagia. All hyperthyroid cases were oligomenorrhoeic. Conclusion: Both hypothyroid and subclinical hypothyroid cases were the commonest thyroid dysfunction and menorrhagia was their commonest menstrual abnormality. So this study concludes that biochemical evaluation of thyroid functioning should be made in all provisionally diagnosed cases of AUB to detect thyroid dysfunction.