The purpose of this study was to determine how the application of methods Contextual Teaching and Learning (CTL), to improve learning outcomes subjects of Natural Sciences of Conservation Effort Lingkungan.Penelitian held in SDN 001 Sesayap Lower Tana Tidung, with research subjects fifth grade students who amounted to 30 people. This research is an action using a model Kemmis and McTaggart, conducted in two cycles. Each cycle consists of planning, implementing action, observation, and reflection action. The results showed an increase in student learning outcomes in subjects of Natural Sciences, in particular concerning environmental conservation efforts, by applying the method of Contextual Teaching and Learning (CTL). This is evidenced by the value of the test results of students in the first cycle that 70% of students who completed, increased in the second cycle to 100% of students who pass. Activities of teachers and students according to the steps of this method reach 100% (mastery learning) at the end of the second cycle. The conclusion of this study indicate that the application of the method of Contextual Teaching and Learning (CTL), enables students to improve learning outcomes Natural Sciences and can develop creativity and can cooperate well. Keywords: Methods Contextual Teaching and Learning (CTL), Learning Outcomes IPA, Enterprises Environmental Conservation, Action Research. Tujuan penelitian ini adalah untuk mengetahui cara penerapan metode Contextual Teaching and Learning (CTL), untuk meningkatkan hasil belajar mata pelajaran IPA tentang Usaha Pelestarian Lingkungan.Penelitian dilaksanakan di SDN 001 Sesayap Hilir Tana Tidung, dengan subjek penelitian siswa kelas V yang berjumlah 30 orang. Penelitian ini merupakan penelitian tindakan dengan menggunakan model Kemmis dan McTaggart, dilakukan dalam dua siklus. Setiap siklus terdiri dari tahap perencanaan, implementasi tindakan, pengamatan, dan refleksi tindakan.Hasil penelitian menunjukkan adanya peningkatan hasil belajar siswa pada mata pelajaran IPA, khususnya tentang usaha pelestarian lingkungan, dengan menerapkan metode Contextual Teaching and Learning (CTL). Hal ini dibuktikan dengan nilai tes hasil belajar siswa pada siklus I yaitu 70% siswa yang tuntas, meningkat pada siklus II mencapai 100% siswa yang tuntas. Aktivitas guru dan siswa sesuai langkah-langkah metode ini mencapai 100% (mastery learning) pada akhir siklus II. Kesimpulan dari penelitian ini menunjukkan bahwa penerapan metode Contextual Teaching and Learning (CTL), membuat siswa dapat meningkatkan hasil belajar IPA serta dapat mengembangkan kreativitas dan dapat bekerjasama dengan baik. Kata kunci:Metode Contextual Teaching and Learning (CTL), Hasil Belajar IPA, Usaha Pelestarian Lingkungan, Penelitian Tindakan.