Adolescence is an important period of transition from girlhood to womanhood. Menstruation is the physiological process that indicates the onset of puberty. The practice of menstrual hygiene also depends on socioeconomic, cultural and religious differences. Menstrual hygiene plays an important role in the overall health of women. The aim of the study is to analyse the knowledge and practice of menstrual hygiene among adolescent girls in the Chennai population. A descriptive cross-sectional survey was conducted among 102 girls of Chennai population to analyse their knowledge and practice of menstrual hygiene through an online survey. A self administered questionnaire was prepared with 10 closed ended questions and circulated among the parents through online survey forms “Google forms”. The responses were collected and statistically analysed by SPSS using chi square test. The results were represented by bar charts and frequency tables.Among the 102 participants 98.8% of them are aware of menstrual hygiene 96.1% of the girls use sanitary pads as the absorbent, and about 99% of them dispose of their used absorbents in dustbins. 94.1% have knowledge on the effect of not following good menstrual hygiene. The study concludes that the girls of Chennai population have adequate knowledge and good practice of menstrual hygiene