Kinetic parameters of thermal decomposition of thiocyanatobismuthates(III) of formulae (NH4)3[Bi(SCN)6], (NH4)2M[Bi(SCN)6] (where M is Li, Na, K, Rb) and NH4Ca[Bi(SCN)6].5H2O have been determined. The thermal stabilities (expressed by initial decomposition temperature and activation energy of the first step of decomposition) of thiocyanatobismuthates(III) containing alkali metal and ammonium group are compared with those of alkali metals in the outer sphere.