Menstruation is a physiological phenomenon unique to adolescent girls. Improper menstrual hygiene can cause reproductive tract infections. A quasi experimental study was conducted among 100 adolescent girls of class 7th and 8th of selected schools in Chennai. The girls were given a pre-tested self structured questionnaire to assess their knowledge and attitude on menstrual hygiene followed by a laptop assisted teaching on menstrual hygiene to the study group for 45 minutes. The control group received the routine teaching. After 7 days a posttest was conducted for both the groups. Majority of the samples in the study group (38%) and the control group (46%) were in the age of 13 years. The overall knowledge on menstrual hygiene in the study group had a mean and SD of 10.70 (2.78) in the pretest and 15.98 (3.38) in posttest which was statistically significant at p<0.001. The control group had a mean and SD of 10.88 (2.93) in the pretest and 11.22 (2.40) in the posttest which was statistically non-significant. The overall mean and SD of attitude on menstrual hygiene in the study group was 43.68 (4.83) in pretest and 49.42 (3.32) in posttest which was statistically significant at p<0.001, whereas in the control group it was 41.68 (5.73) in pretest and 42.20 (4.33) in posttest, which was statistically non-significant. There was positive correlation between the level of knowledge and attitude in study and control group in both pre and posttest. It was concluded that the adolescent girls should be definitely educated about the maintaining menstrual hygiene.