Abstract: An aqueous high concentration coal slurry having a high dispersion stability is produced by a process in which a coal material is wet pulverized at a low concentration in a dispersing agent-free aqueous medium, the resultant coal slurry is hydrated, the dehydrated coal cakes are mixed with an aqueous dispersing additive solution to provide an aqueous coal slurry (A), a portion (B) of the slurry (A) is further pulverized, and the pulverized portion (B) is mixed with the remaining portion (D) of the slurry (A), or by a process in which a coal material is pulverized in an aqueous dispersing agent solution to provide a slurry moiety (E), separately a cake moiety (E) is provided, the slurry moiety (E) is mixed with the cake moiety (E) the above-mentioned process being carried out to an extent such that the resultant coal slurry contains coal particles having a size of 5 .mu.m or less in a content of 15% by weight or more and coal particles having a size of 500 .mu.