The synthesis, characterization and thermal decomposition of pyridinium uranyl acetate are presented. The identification of the compound was performed by chemical analysis and by infrared spectroscopy. Thermal decomposition of pyridinium uranyl acetate took place in several steps due to the decomposition of the salt to UO2, and to partial oxidation to UO3 and formation of U3O8 The intermediate and the final products of thermal analysis were identified by means of thermogravimetric, differential thermal analysis and X-ray powder diffraction.