This research aimed to find out the effectiveness of the insertion learning method towards the instilling of environmental care character on the subject matter of Natural Disaster Mitigation. This was a classroom action research conducted in two cycles consisting of two meetings. Each cycle included four steps that were planning, acting, observing, and reflecting. This research was conducted in semester II in the academic year of 2019/ 2020 with the subjects of 37 students consisting of 27 females and 10 males. The instruments used in this research were the students' activity observation sheet and the questionnaire sheet of instilling environmental care character. The results showed that the implementation of the insertion learning method ran well as it was planned, was effective, and appropriate. It was even very effective. So, it could be concluded that there was the effectiveness of the insertion learning method toward the instilling of environmental care character on the subject matter of natural disaster mitigation on the eleventh grade of SMA Negeri 1 Ajibarang.