Experimental evidence for the production of hot electrons in an acetonitrile solution from a Ta2O5-covered Ta electrode was provided by electrogenerated chemiluminescence (ECL) and electrochemical measurements. Electron transfer to solution species occurred via the Ta2O5 conduction band, as demonstrated by comparative measurements with a number of one-electron redox couples at Pt and Ta electrodes. The oxidized forms of thianthrene and a heptamethine cyanine dye were selected as the species capable of direct formation of the excited state and ECL upon hot electron injection. The observation of ECL emission upon a cathodic potential step (a process that does not occur at a metal electrode) confirmed the occurrence of this process. ECL emission at Ta/Ta2O5 was also observed during reduction of Ru(bpy)(3)(3+) (bpy = bipyridine). Reasons for the low efficiency of the ECL process via hot electrons at the metal/metal oxide/solution interface are discussed.