Abstract. A study concerning macro soil nutrient elements produced through cow feces composting process by Trichoderma sp. was conducted at Field Laboratory Peternakan (LLP) and at Soil and Plant Research Laboratory, Faculty of Agriculture, Syiah Kuala University from June to December 2018. The objective of this research was to determine macro soil nutrient elements (N, P, K, and C) produced, and to calculate C/N ratio value, from the result of composting cow feces that was applied with Trichoderma sp. Completely Randomized Design was used in this research with 4 treatments (P0 = control/0% Trichoderma sp applied, P1 = 1% Trichoderma sp applied, P2 = 3% Trichoderma sp applied, and P3 = 5% Trichoderma sp applied) and 4 replications. The amount of N, P, K, C, and the value of C/N ratio were the parameter observed. The statistical analisis indicated that there was no significant effect (P>0,05) caused by treatments on P, K, C and C/N parameters, there is a significant effect (P0,05) yang disebabkan oleh perlakuan pada parameter P, K, C dan C/N, Pengaruh yang signifikan (P