Cyclic voltammetry and potential step measurements were performed on platinum, gold and glassy carbon electrodes in molten cryolite and cryolite-alumina melts containing SnF2, SnO2 or SnO. The reactions involving dissolved tin species were found to behave more reversibly using a gold electrode. The voltammograms showed peaks attributed to the presence of two oxidation states of tin in the melt, ie Sn(II) and Sn(IV). Some waves were accompanied by current oscillations due to the formation of volatile species, probably SnF2 and SnF4. These oscillations were not observed in melts containing dissolved Al2O3, which presumably stabilizes the tin compounds. Some of the voltammograms gave indications of anodic precipitation of SnO2 on platinum. Such precipitation was confirmed using potential step measurements.