First aid is a fundamental skill for every human of every age, so training in first aid is necessary at a variety of levels. First aid training in schools is essential, but to date, only short reports have been published on the effectiveness of first aid training in kindergarten. We conducted a pilot randomized controlled study on the impact of first aid training on children in kindergarten. We randomly selected 24 children aged 4-5 years from one kindergarten, who were allocated to either a training group (14 children) or a control group (10 children). The training program consisted of three lessons. An eleven-question questionnaire was administered to the children in the training group one day before, one day after, and two and six months after the training, and once to the those in the control group. Before the training, no significant difference was detected in the score on the questionnaire between the two groups. After the lessons, the children in the training group scored significantly higher on the questionnaire than before the lessons, and than the children in the control group. At two and six months after the training, the scores of the children in the training group had decreased but remained higher than before the training and higher that those of the control group. These preliminary results indicate that kindergarten children may benefit from first aid training, but further studies are needed to verify these observations and to explore ways of maintaining the knowledge acquired in training.