Unintentional injuries are a major cause of death among children. Data suggest that the retention of knowledge and skills about first aid declined over time. The purpose of this study was to assess the effects of pediatric first aid training among teachers. Methods: A stratified random sampling method was used to select 1,067 teachers. The selected trainees received pediatric first aid training. Follow-up assessments were conducted 6 months, 9 months and 4 years following the training. A standardized collection of demographics was performed, and participants were given a questionnaire to indicate knowledge of and emotions about first aid. Results: In the pretest, 1067 people responded with a mean of 21.0 correct answers to 37 questions, whereas in the post-test period, the mean score increased to 32.2 correct answers of 37 questions (P <0.001). There was a decrease in scores from post-test to 6 months, 9 months and 4 years after the training. However, the mean at the 6-month, 9-month and 4-year marks were higher than the pretest mean (P < 0.001). A total of 82.8% of the participants achieved a pass mark of 80% or above; 42.8% of participants achieved the pass mark at 6 months, 41.7% at 9 months and 11.7% at 4 years (compared with pre-test, P < 0.001). The mean score of the subjects' emotions in the post-test period increased to 81 (P < 0.001). The mean scores of emotions at 9 months or 4 years were higher than the pretest mean (P < 0.001). At the 4-year mark, the majority of preschool staff (>70%) had administered correct first aid for injuries. Conclusions: This study demonstrated that the acquisition of knowledge, both short and long term, significantly improves. Despite appreciable decreases in knowledge long term, knowledge retention was modest but stable. (author abstract)