Electrochemical formation of Sm-Co alloy films at a Co cathode was studied in a molten LiCl-KCI-SMCl3 (0.5 mol.%) at 723 K. Very thin film similar to 100 nm) Of SMCo2 alloy was obtained by potentiostatic electrolysis at 0.20 V (vs. Li+/Li) for 24 h. Much thicker alloy film (similar to5 mum) was formed by Li codeposition method (cathodic galvanostatic electrolysis at 50 mA cm(-2)) for I h. The formed alloy phase was suggested as LixSM4Co6 (x similar to 3). The formed alloy film was changed to various Sm-Co alloy phases by anodic potentiostatic electrolysis depending on the applied potentials. The formation potentials Of SM2CO17, SMCo3, SMCo2 and LixSm4Co6 were found to be 1.40, 0.80, 0.30 and 0.05 V, respectively.