Introduction : Cardiac arrest is a common health issue in modern days and one of the emerging health issues in present days. One-third of clients required cardiopulmonary resuscitation (CPR) before reaching to the hospital. Therefore, some countries have been implanted Basic life support training compulsory for teachers and students. Method : A quantitative cross-sectional pilot study was conducted among school teachers. A total of 22 participants were selected using a non-probability purposive sampling technique. An evaluated the effectiveness of basic life support (BLS) among school teachers on Knowledge, attitude, and practice. The pretest was assessed before the intervention and the post-test assessment was assessed at the end of the 5th day. Result : On assessment, the majority of participants was male (72.7%), married 16(72.7%), and aged between 20 and 30 years old 10 (45.5%). Of the 14.3% of graduates, teaching experience varied from 6 to 10 years 16 (72.7%), and the majority of them were science teachers 17 (68.2%). The majority of teachers, 17 (68.2%) were Hindu don’t have previous knowledge of 17(77.3%). There was a correlation between knowledge score and gender, experience, designation, and prior knowledge. Before the intervention of basic life support training, the majority of participants had poor knowledge12 (56.6%), post-test improved good knowledge 20(90.9%). Similarly, in the pretest, most of the participants had a negative attitude 16(72.7%),and a few after BLS showed a positive attitude 20(90.9%). Pretest practice skills had inadequate 17 (77.3%), moderate knowledge 5(22.7%), After the intervention, most of them 20(90.9%) had good knowledge. Conclusion : Basic life support (BLS) is the most effective intervention for school teachers. Most of the school teachers improved the knowledge, attitude and practice after the intervention.