The thermal decomposition of anhydrous bismuth citrate in dynamic air or nitrogen has been studied. The encountered thermal events have been monitored by means of TG, DTA and DSC and the decomposition solid products analysed by IR spectroscopy and X-ray diffractometry. Non-isothermal and thermodynamic parameters have been estimated for each encountered thermal event. The results show that bismuth citrate decomposes via two events occurring exothermically in air and endothermically in nitrogen. The decomposition takes place through the formation of an intermediate composed of bismuth oxide acetate in addition to bismuth oxides in different phases. A decomposition scheme is proposed and the associated morphological and structural changes have been followed by scanning electron microscopy.