Abstract Background: Adolescence is a transitional stage extending from 10-19 years characterized by rapid physical, mental and sexual changes. It is also characterized by hormonal changes. As girls attain puberty at this age, they have various problems associated with menstruation. Aim: The aim of the present study was to determine the menstrual pattern and various menstrualproblems among urban adolescent girls. Material and methods: This was a cross sectional study conducted in the Department of Obstetrics & Gynaecology, NSMCH, Bihta, Patna, Bihar, India, for 18 months. 110 adolescent girls randomly who presented with menstrual problems in gynaecology OPD were included in this study. Total of 110 girls were asked to fill up a questionnaire which included questions like age of menarche, pattern of menstruation, duration and amount of flow, number of pads used. Result: Majority of girls (63.63%) attained their menarche between 10-13 years of age and remaining 36.37% were in the age group of 14-16 years. Majority of girls had problem of oligomenorrea (60.91%). 25.45% of girls had normal cycle length of 28-35 days and only 8.18% had frequent bleeding with cycle length less than 28 days. But duration (3-5 days) and quantity of flow was normal in maximum girls 80% and 62.73% respectively. Excessive flow with passage of clots or duration of flow for more than 5 days was noted in 20% and 13.64% of girls respectively. Conclusion: Menstrual problems are present in majority of girls in the study group which has some effect on the academic performance and other extracurricular activities in school.