Hydrogen exchange reaction of four Argonne coals (Beulah-zap (ND), Illinois No.6 (IL), Upper Freeport (UF) and Pocahontas #3 (POC)) with tritiated water using a batch reactor was performed at several time and temperatures. The amounts of aromatic hydrogen at ortho and para positions of a functional group could be calculated to be 2.7, 2.3, 0.9 and 1.7, for ND, IL, UF and POC, respectively. In the reaction of model compound of coal with deuterium oxide, aromatic hydrogens at ortho and para positions of such compounds with hydroxy and amino groups as phenol and aniline are exchangeable.