This paper is an experimental study regarding activated carbon of peanut shells on rheology and filtration loss of drilling mud. Rheology and filtration loss are essential characteristics of mud that in controlling the accomplishment of drilling operations. This research begins by activating carbon from peanut shell waste (KKT) with three different activation temperatures, e.g., 700, 800, and 900°C. We conduct Rheology, i.e., absolute, plastic viscosity, yield point, and gel strength, to observe the effect of carbon activation temperature of KKT additive to those parameters. Moreover, filtration tests to determine mud-cake thickness also become one part of this study. The results showed that the mud sample with 5 g KKT activated carbon at 900°C activation temperature shows the best performance among all samples. Result from both rheology and filtration test yields 5 cp plastic viscosity, 10 yield point, 0.4 gel strength, the volume of the filtrate is 16 ml, and the mud cake is 0.16 cm. [ABSTRACT FROM AUTHOR]