Gasification is a combustion process that can converts waste into electricity. Tar waste is liquid waste from the gasification process that has not been managed and utilized. Tar waste contains toxic compounds that can pollute the environment if they enter it. Tar waste has the potential to be used as a raw material for disinfectants because it contains phenol and polycyclic aromatic hydrocarbon (PAH) compounds This study aims to determine the potential of tar waste as a disinfectant based on antibacterial activity tests and phenol coefficient tests with Salmonella typhimurium bacteria. Tar waste was tested for its antibacterial activity to determine the effective concentration between with concentrations of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100% that has the potential to be an active ingredient in disinfectants. The effectiveness of the disinfectant was measured by the coefficient value of tar waste compared to 5% phenol against the Salmonella typhimurium test bacteria. If the coefficient value is equal to or greater than 1, it is said that tar waste is effectively used as a disinfectant. The results showed that the effective concentration of tar waste as a raw material for disinfectant through the antibacterial activity test was 100% with an inhibition zone diameter of 0.275556 mm in the weak category. The phenol coefficient value of 100% tar waste is 0.05. The conclusion of this study is that tar waste with a concentration of 100% is not yet effective as a raw material for disinfectant according to SNI 1842:2019.