In order to improve the gas evolution rate during anaerobic digestion of coffee waste by two-phase methane fermentation with slurry-state liquefaction, the liquefaction and gasification processes were separately investigated. In the liquefaction process (including the acidification process), treatment at a pH above 6 had no major effects on the liquefaction and acidification rates. However, the VFA production rates were 880 and 320 mg/l.d during mesophilic (37-degrees-C) and thermophilic (53-degrees-C) liquefaction, respectively. Mesophilic conditions were superior to thermophilic conditions in the liquefaction. With respect to the gasification process, a high TOC volumetric loading rate of 21 g/l.d was achieved during thermophilic gasification. However, the mesophilic gasification did not yield stable data, even at a low TOC volumetric loading rate of 2 g/l.d. The gas yield was 1.7 l/g TOC consumed during thermophilic gasification. The thermophilic liquefaction and thermophilic gasification reactors were connected in series and a two-phase experiment was conducted with the reactors at various volumetric ratios. The maximum gas evolution rate of 1.43 l/l.d was achieved with a combination of a gasification reactor with a 0.45 l working volume and a liquefaction reactor with a 2l working volume. This rate was 1.7 times higher than the rate obtained in a previous study.