Abstract This study aims to make a catalyst from biomass waste in the form of coconut coir and apply it to the transesterification process of cocodiesel. The raw material for cocodiesel in this study was a coconut-based cooking oil that was also a waste and could pollute the environment. The research method includes cooking oil analysis, the catalyst’s preparation, and the catalyst’s characterization with Brunauer-Emmet-Teller (BET), X-ray fluorescence (XRF), X-ray diffraction (XRD), and Scanning electron microscope (SEM) analysis. The next step was the application of the catalyst in the transesterification reaction. The results showed interesting information, in which the addition of the calcination process increased the catalyst’s surface area and crystallinity ratio. Applying a catalyst in converting used cooking oil to cocodiesel gave 48.5% and 51% yields with densities close to the biodiesel standard.