The phase of a model garbage was changed from solid to liquid slurry by thermal liquidization for the purpose of easy handling. The garbage was prepared by mixing cabbage, boiled rice, boiled and dried sardine, butter, and the shell of short-necked clam, and its moisture content was 86.4 wt%. It was heated under a pressurized nitrogen atmosphere at 150, 200, or 250 degrees C for 0.1 or 1 h with or without sodium carbonate as a catalyst (5% on a dry solid basis). In the liquidized garbage produced, the solid particles were suspended. Slight sedimentation of the particles was observed for the liquidized garbage obtained at 150 and 200 degrees C, however the particles settled rapidly for the liquidized garbage obtained at 250 degrees C. The liquidized garbage was regarded as a pseudoplastic fluid from viscosity measurements, and the apparent viscosity decreased significantly with the reaction temperature.