Background: 75% of girls experience some problem associated with menstruation the prevalence of menstruation irregularities in obese women has been reported to range between 8% and 18%. A dysmenorrheal includes 33.5%, among adolescents in India (87.7%).

Aim: The aim of the study was to assess the relationship between body mass index (BMI) and menstrual irregularities among adolescent girls.

Objectives: 1.To assess the menstrual irregularities and BMI among adolescent girls. 2. To find the relationship between menstrual irregularities and BMI among adolescent girls. 3. To find out the association between menstrual irregularities and BMI with demographic variables of adolescent girls. Methodology: 50 adolescent girls were selected from Narayana college of Nursing, Nellore by using non probability purposive sampling technique.

Results: The study concluded that there was a co-relation between BMI and menstrual irregularities (0.94).