In this study, the gasification performance of coal water ethanol slurry (CWES) was estimated in a pilot-scale entrained flow gasifier. CWES was prepared by adding ethanol into coal water slurry (CWS) to estimate the gasification performance of bioethanol-contained coal water slurry. In comparison to CWS gasification, gasification with CWES showed a higher performance, such as composition of hydrogen and carbon monoxide, carbon conversion, cold gas efficiency, and total flow rate of syngas. In general, the gasification performance is directly associated with the carbon content of CWS, and it is very difficult to increase the carbon content of CWS while maintaining slurry viscosity to the atomizable level (2000 cP). However, in the case of CWES, the carbon content of slurry can be readily improved and the viscosity of slurry can be reduced at the same time. Thus, the improved carbon content of CWES led to a higher gasification performance than that of CWS. Moreover, if bioethanol is actually used for the preparation of CWES, carbon dioxide emission from gasification could be considerably diminished.