Background: Adolescence is a crucial phase of growth extending from puberty to adulthood spanning much of the second decade. It is the critical period of biological and psychosocial changes. They lack adequate knowledge about the physical changes during the pubertal period and which in turn leads to undue anxiety. Objectives: The objectives of the study were to assess the knowledge, perception, psycho social preparedness for menarche and the problems experienced by the adolescent girls. Methods: A descriptive survey study was conducted among 200 adolescents aged 11-13 years from 10 higher primary schools of Udupi district. Adolescents who met the sampling criteria were selected by purposive sampling. Structured questionnaire was used to assess the knowledge on menarche. A rating scale was used to assess the perception, psychosocial preparedness towards menarche and predesigned questionnaire was used to assess the problems experienced at the time of menstruation. Descriptive and inferential statistics were used for data analysis. Results: Results shows that, out of 200 adolescents, 88% of the adolescents had average knowledge, 95.5% had negative perception, most of them 52.5% were well prepared for menarche. The most common problems experienced by the adolescents were abdominal pain (75%), heavy bleeding (73.5%) and white discharge few days before menstruation. Conclusion: Social prohibitions and restrictions from attaining religious rituals have created a negative impact on adolescents and have blocked the access to the right kind of information. Therefore much more efforts are needed to curb the misbeliefs and taboos among the adolescent school girls.