Objectives: To assess the existing knowledge regarding prevention of hepatitis B among the [13-16] years school age children at Chidambaram. To evaluate the effectiveness of structured teaching of hepatitis B among the [13-16] years school age children at Chidambaram. Method: The present study was conducted on a sample of 100 school children. A quasi experimental design was used. The structured interview schedule was used to collect the data. Result: The pre test revealed that the knowledge on prevention of hepatitis B among the [13-16] years school age children before the STP programme, 94 (94%) students had inadequate knowledge and 6 (6%) students had moderately adequate knowledge. After the STP programme, in the post-test 13 (13%) students had moderately adequate knowledge and 87 (87%) students had adequate knowledge on prevention of hepatitis. This reveals that the STP was very effective and improved the knowledge level of the students on hepatitis. Conclusion: This study demonstrated that the knowledge of the students regarding the prevention of hepatitis A, B and C was inadequate after the Structured Teaching Programme the knowledge has improved.