New methods were applied in the synthesis of double salt iodates of the type K2M(IO3)4 . 2H2O (where Me is Co2+, Ni2+, Zn2+). Their thermal and calorimetric behaviour were investigated by DTA, TG and DSC. Simultaneous dehydration and decomposition of the binary salt give simple iodites. Mixtures of KIO3 and Me(IO3)2 were melted, followed by the latter’s decomposition along familiar pathways. The DELTAH(ph,tr)theta values were recorded from the DSC curves, while the TG curves were processed by the methods of formal kinetics, and the kinetic parameters E* and A calculated. The type of kinetic equation for the dehydration process was also determined.