Indonesia has an abundant resource of natural zeolite due to its geological location involcano pathway. This material has been widely employed in various processing technologies. Inspite of the diverse applications, the usage of zeolite in the hydrothermal treatment (HT) of waste israrely found. Recently, HT shows a promising technology for municipal solid waste (MSW)treatment. The main objective in this research is to study the influence of zeolite addition in HT ofMSW in terms of liquid product properties. In this research, equal weight of sawdust and crushedplastic bottle waste (PET) were used to represent MSW. The waste mixture was loaded into a 2Lbatch reactor with zeolite addition from Min (0%) to 20%wt. using 220oC temperature treatment.The liquid side product was then investigated in terms of organic compounds, functional groups,potassium (K) and phosphate (P) contents. It is assigned that zeolite addition enhancesdecomposition process of the MSW into various organic compounds as well as improving P ad Kconcentration in liquid product that can be utilized for fertilizer preparation.