Thermal decomposition of a few itrogenous salts, viz. ammonium sulphate, ammonium nitrate and barium nitrate in vacuum and ammonium chloride in the presence of UO₃was studied over a temperature range 373–1273 K with an aim to understand their thermal decomposition behaviour. The relative amounts of various gaseous oxides of nitrogen formed were compared.Attempts were also made to explain the amounts of different gaseous oxides formed on the basis of the nature of the nitrogenous salts.