Abstrak. Tujuan penelitian ini adalah menginventarisasi dan menginvestigasi kandungan C organic, N, P, K dan C/N ratio pada bahan-bahan organik, dan membuat buku tentang kandungan C organik, N, P, K dan C/N ratio pada daun buah-buahan (penelitian awal), selanjutnya pada bahan lainnya. Pelaksanaan penelitian dilakukan dengan pengumpulan daun buah-buahan yang banyak ditanam di pekarangan petani;, penjemuran bahan, penepungan bahan serta analisa kandungan C organik, N, P, K dan C/N ratio bahan di Laboratorium Ilmu Tanah Faperta Unmul. Hasil analisis laboratorium memberi informasi 100% (masing-masing 13 bahan) mempunyai kandungan C-organik dan N Total dengan status sangat tinggi ; 92,30% (12 bahan) mempunyai Rasio C/N ≤ 35, sisanya 7,697% (1 bahan) mempunyai Rasio C/N ≥ 30; 100% bahan (13 bahan) memiliki kandungan P Total Sangat rendah dan; 38,46% (masing-masing 5 bahan) dengan K Total sangat tinggi dan tinggi, 15,38% (2 bahan) rendah, 7,69% (1 bahan) sangat rendah. Sebanyak 12 bahan yang disidik memiliki rasio C/N memenuhi referensi sebagai bahan yang memadai sebagai bahan pupuk organik; sisanya1 bahan mempunyai rasio C/N di atas referensi sebagai bahan yang memadai sebagai bahan pupuk organik, yang memerlukan penanganan untuk menurunkan rasio C/N sebelum dijadikan bahan kompos. Abstract. The purpose of this study is to inventory and investigate the content of organic C, N, P, K and C / N ratio in organic materials, and make a book about the content of organic C, N, P, K and C / N ratio in fruit leaves (preliminary research), then on other ingredients. The research was carried out by collecting fruit leaves which were widely planted in the farmer's yard ;, drying materials, ingredient sealing and analyzing the content of organic C, N, P, K and C / N ratio of materials at the Faperta Unmul Soil Science Laboratory. The results of the laboratory analysis provide 100% information (13 ingredients each) having a very high C-organic and N content with a very high status; 92.30% (12 materials) have a C / N ratio ≤ 35, the remaining 7.697% (1 ingredient) has a C / N ratio ≥ 30; 100% of the ingredients (13 ingredients) have a very low Total P content and; 38.46% (5 materials each) with total K very high and high, 15.38% (2 ingredients) low, 7.69% (1 ingredient) very low. A total of 12 ingredients that were investigated had a C / N ratio meeting the reference as an adequate material as an organic fertilizer material; the remaining 1 material has a C / N ratio above the reference as an adequate material as an organic fertilizer, which requires handling to reduce the C / N ratio before it is made into compost material.