Any uterine bleeding outside the normal volume, duration, regularity or frequency is considered abnormal uterine Bleeding. Menorrhagia / hypermenorrhea is a pattern of AUB- defined as cyclic bleeding at normal intervals, which is excessive in amount or duration. BMI is a simple index of weight for height. It is defined as a person’s weight in kilograms divided by the square of height in meters and expressed in kg/m2 
Aims and Objectives: To establish the association between body mass index and menstrual disturbances between age group 20-40yrs.
Materials And Methods: Consent of patients taken. A prospective study was conducted in BMCRI over a period of 6 months and 100 patients were included in the study. Patients with age ranging from 20-40yrs, coming to gynaec OPD with presenting history of menstrual irregularities were included. Patients with normal cycles, pregnancy were excluded. Data regarding age, marital status, parity, symptoms, menstrual history, obstetric history, examination, co morbidities, investigation findings, associated pathology and treatment modality were noted. They were tabulated and analysed.
Conclusion: BMI plays a very important role in menstrual cycle regulation. Life style modifications and nutritional counselling could decrease the incidence of menstrual irregularities. Healthy eating habits and maintaining optimal BMI improves menstrual health.