Influence of cobalt salts of aliphatic and aromatic acids has been studied on the burning rates of NC-NG based double phase propellants in the pressure range of 35-140 kg/cm(2). Cobalt-beta-resorcylate has the highest burning rates, followed by cobalt salicylate. Both the compounds show plateau effect in 105-140 kg/cm(2) pressure region. Cobalt stearate is found to be effective in low pressure region, whereas cobalt benzoate is most effective in higher pressure. Cobalt gaIlate is ineffective towards any catalytic or plateau effect. The results have been explained on the basis of thermal decomposition studies of catalysed double base propellants.