Takashi Fujiwara1, Mai Nishimura2, Ryoko Honda3, Takashi Nishiyama4, Masahiro Nomoto5, Naoto Kobayashi6, Masayuki Ikeda71Division of Educational Training, Kurashiki Central Hospital, Kurashiki, Japan, 2Sixth-year medical student, 3Department of Anaesthesiology and Resuscitology, 4Department of Emergency Medicine, 5Department of Therapeutics, 6Medical Education Center, Ehime University School of Medicine, Ehime, Japan, 7Graduate School of Biomedical Sciences, Nagasaki University School of Medicine, Nagasaki, JapanBackground: The effect of peer-led training in basic life support (BLS) in the education of medical students has not been assessed.Subjects and methods: This study was a randomized controlled trial with a blinded outcome assessor. A total of 74 fourth-year medical students at Ehime University School of Medicine, Japan were randomly assigned to BLS training conducted by either a senior medical student (peer-led group) or a health professional (professional-led group). The primary outcome measure was the percentage of chest compressions with adequate depth (38–51 mm) by means of a training mannequin evaluated 20 weeks after BLS training. Secondary outcome measures were compression depth, compression rate, proportion of participants who could ensure adequate compression depth (38–51 mm) and adequate compression rate (90–110/minute), and retention of BLS knowledge as assessed by 22-point questionnaire.Results: Percentage chest compressions with adequate depth (mean ± SD) was 54.5% ± 31.8% in the peer-led group and 52.4% ± 35.6% in the professional-led group. The 95% confidence interval (CI) of difference of the means was –18.7% to 22.8%. The proportion of participants who could ensure an adequate mean compression rate was 17/23 (73.9%) in the peer-led group but only 8/22 (36.4%) in the professional-led group (P = 0.011). On the 22-point questionnaire administered 20 weeks after training, the peer-led group scored 17.2 ± 2.3 whereas the professional-led group scored 17.8 ± 2.0. The 95% CI of difference of the means was –1.72 to 0.57.Conclusion: Peer-led training in BLS by medical students is feasible and as effective as health professional-led training.Keywords: basic life support, education, training, randomized controlled trial