Disclosed are methods of manufacturing negative electrode slurry for all-solid-state batteries, negative electrodes manufactured by the methods, and all-solid-state batteries including the negative electrodes. The method of manufacturing a negative electrode slurry includes preparing a first mixture by mixing a negative electrode material with a binder solution that includes a solvent and a first binder, producing a dispersion by performing an ultrasonic dispersion treatment on the first mixture, and preparing a second mixture by adding a second binder to the dispersion.