BackgroundAdolescence in females signifies the transition from girlhood to womanhood and is marked with the onset of menarche. Indian society is interwoven into a set of traditions, myths and misconceptions, especially regarding menstruation and related issues. The present study was conducted to assess knowledge and psycho-social behavior related to menstruation among adolescent girls in urban Haryana (state), India. Method A total of 478 adolescent girls in the age group of 15 -19 years from three educational institutes of Rohtak city were selected randomly. It was a community-based, descriptive, cross-sectional questionnaire based study, and a pre-tested, pre-coded, closed ended questionnaire was used. Results Feeling of sickness was the most common (in more than two-third of subjects) followed by irritability and emotional disturbances. More than 3/4th of the subjects did not worship during menstruation, 45% were not allowed in kitchen and nearly one-fourth followed dietary restrictions. More than 16% subjects thought menstruation to be a sign of onset of a disease and little more than 7 % thought it to be a curse. Girls preferred to discuss their menstruation related problems either with their mothers or with their friends. ConclusionGirls have inaccurate and partial information regarding menstruation. There is a need of early intervention in the area of adolescent psycho-social behavior during menstruation