RESUMEN
<b>Background and Objective:</b> Plant litter or plants that grow naturally and the plant materials of the cultivated plants are quite abundant both in fresh and dry form. In the case of a plant, litter is not processed and left on the surface of the soil as organic material then the process of decomposition and reshuffle requires a long time. The research aimed to find out the effectiveness of bio-activators on the formation and quality of compost fertilizer. <b>Materials and Methods:</b> The study design was used in a factorial pattern with two factors. The First factor is bio-activator consists of four levels, namely: EM-4, PROMI, Orgadec and (EM-4+PROMI+Orgadec). The second factor is organic matter consists of seven levels, namely: <i>Imperata cylindrica</i>, paddy straw, <i>Gliricidia sepium</i> leaves, (<i>Imperata cylindrica</i> + paddy straw), (<i>Imperata cylindrica</i> + <i>Gliricidia sepium</i> leaves), (paddy straw + <i>Gliricidia sepium</i> leaves), (<i>Imperata cylindrica </i>+ paddy straw + <i>Gliricidia sepium</i> leaves). There were 28 treatments, each treatment was repeated three times to obtain 84 treatment units. <b>Results:</b> The result showed that compost fertilizer with Orgadec bio-activator treatment and PROMI is the best quality (pH compost, water content, P-total, N-total, C-organic, C/N ratio). <b>Conclusion:</b> The compost fertilizer with Orgadec bio-activator is the best quality for this research (pH compost, moisture content, P-total, N-total, C-organic, C/N ratio).