Cassava peel is a natural material that is still underutilized even though has the potential as an alternative to activated carbon precursors. In the synthesis of activated carbon, the impregnation ratio and activation temperature are important factors that affect the characteristics of the activated carbon produced. This study aims to determine the effect of variations in the impregnation ratio (carbon: H3PO4) and activation temperature on the characteristics of activated carbon from cassava peel (CPAC) and to determine the optimal conditions in the manufacture of CPAC. In this study, CPAC was produced by treatment with various impregnation ratios of 1:5, 1:6, 1:8, 1:10, and 1:12 (w/w, carbon: H3PO4 30%) and a range activation temperature variation of 400 - 800 °C in the furnace for 60 minutes. The CPAC results were analyzed using FTIR, XRD, and SEM-EDX instruments. Based on the results of the FTIR test, it is showed that the characteristics of CPAC contain functional groups O–H, C–H, C≡C, C=C, C–O/P=O with an impregnation ratio of 1:6 (w/w, carbon: H3PO4 30%) and an activation temperature of 500 °C for 60 minutes to be the optimal conditions in the production of CPAC. The CPAC has an amorphous crystalline character based on XRD analysis and a hollow (porous) surface based on SEM analysis. The results of the EDX test showed that CPAC consisted of the elements carbon (C), oxygen (O), nitrogen (N), phosphate (P), sodium (Na) with the respective percentages being 72.60%, 15.52%, 10 .32%, 1.09%, and 0.47% respectively.