Tujuan penelitian ini untuk mengetahui pengaruh dosis penggunaan suplemen organik cair (SOC) tauco terhadap kualitas dedak padi fermentasi yang diukur berdasarkan kadar asam laktat, pH, susut bahan kering, dan nilai Fleigh. Penelitian ini dilakukan di Laboratorium Nutrisi Ternak Ruminansia dan Kimia Makanan Ternak Fakultas Peternakan Universitas Padjadjaran. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) yang terdiri atas tiga perlakuan dan enam ulangan dimana P0 (1000 gram dedak padi : 300 gram molasses), P1 (1000 gram dedak padi : 200 gram molasses : 100 gram SOC) dan P2 (1000 gram dedak padi : 100 gram molasses : 200 gram SOC). Data yang diperoleh diolah dan dianalisis ragam dan uji lanjut jarak berganda Duncan menggunakan software SPSS versi 27. Hasil penelitian menunjukkan bahwa penggunaan suplemen organik cair (SOC) tauco memberikan pengaruh yang sangat signifikan (p<0,01) terhadap asam laktat, pH, susut bahan kering dan nilai Fleigh. Dapat disimpulkan bahwa penggunaan suplemen organik cair (SOC) tauco pada perlakuan P2 menghasilkan produk dedak padi fermentasi terbaik berdasarkan pH (4,75), asam laktat (25,17%), susut bahan kering (2,80%) dan nilai Fleigh (168,72). ABSTRACT The purpose of this study was to determine the effect and dosage of the use of liquid organic supplement (LOS) tauco on the quality of fermented rice bran. The quality of fermented rice bran was measured based on lactic acid content, pH, dry matter loss, and Fleigh value. This research was conducted at the Laboratory of Ruminant Animal Nutrition and Animal Food Chemistry, Faculty of Animal Science, Padjadjaran University. This study used a completely randomized design (CRD) consisting of three treatments and six replications where P0 (1000 grams of rice bran: 300 grams of molasses), P1 (1000 grams of rice bran: 200 grams of molasses: 100 grams of LOS) and P2 (1000 grams of rice bran: 100 grams of molasses: 200 grams of LOS). The data obtained were processed and analyzed for variance and Duncan's multiple range further test using SPSS software version 27. The results showed that the use of liquid organic supplements (LOS) tauco gave a very significant effect (p<0.01) on lactic acid, pH, dry matter loss and Fleigh value. It can be concluded that the use of liquid organic supplement (LOS) tauco in treatment P2 produces the best fermented rice bran product based on pH (4.75), lactic acid (25.17%), dry matter loss (2.80%) and Fleigh value (168.72).