Gamma-radiolysis of KNO3 in the matrix of some sulfates, viz. Na2SO4, K2SO4, KNaSO4, KNaSO4: Eu, KNaSO4: Ce, K3Na(SO4)2, K3Na(SO4)2: Eu and K3Na(SO4)2: Ce has been studied at an absorbed dose of 30 kGy.G(NO
) values calculated on the basis of electron fraction in all the sulfates are enhanced significantly. It is also affected by the nature of outer cation and the dopant lanthanide. Electron spin resonance (ESR) and thermoluminescence (TL) measurements show the formation of radical species SO
upon -irradiation. It is proposed that there radical species may transfer energy and interact with the radical species of nitrate (NO
, NO2, NO3 etc.) so as to enhance the decomposition. A possible mechanism has been proposed.