BACKGROUND: The aim of the study is to evaluate the theoretical knowledge and psychomotor skill acquisition of basic life support (BLS) by a group of secondary school students in Nigeria pre and post BLS training. METHODS: This was quasi-experimental study design with 210 participants. They were taught on adult BLS and all the participants practiced BLS on a Resusci-Anne manikin immediately after the training. Data were collected using American Heart Association (AHA) structured questionnaire and psychomotor skills checklist for BLS at baseline, and post BLS training. RESULTS: The pre-training knowledge score was 1.9±1.4. This increased after the BLS training to 11.4±2.4, and the mean difference between the pre and post BLS training scores was 9.48571. Pre-training psychomotor skill score was 0.00±0.00, this increased to 8.9±1.9 after the training, and the mean difference was 8.90000. The knowledge and psychomotor skill difference between pre and post BLS training was significant (P<0.000). CONCLUSION: Most Nigerian secondary school students were not knowledgeable about BLS. Therefore, there is need for the creation of more awareness among the students.