Mixed yttrium-copper oxides, some containing several percent barium, have been deposited cathodically on CuO/Cu substrates from eutectic Na-K nitrate melts (300-degrees-C) containing dissolved Y3+ and Ba2+ nitrate species. Cobalt oxide (Co3O4) has also been deposited from this system by cathodic reduction of Co3+ nitrate ions at a Pt electrode. Available data for Na-K nitrate melts have been summarized to facilitate the design of schemes for deposition of various mixed metallic oxides.