The solubility of LaCl3 in acidic AlCl3-1-ethyl-3-methylimidazolium chloride (AlCl3-EMICl) ambient temperature melts at 298 K increases as the acidity of the melts increases. When LaCl3 was dissolved in the melt (molar fraction of AlCl3, N = 0.667), Raman spectra of AlCl4- and Al2Cl7- anion were observed. From these results, the dissolution reaction in the acidic melts is thought to be: 3Al(2)Cl(7)(-) + LaCl3 reversible arrow La(III)+ 6AlCl(4)(-). Electrochemical measurements and potentiostatic electrolysis were performed in various LaCl3 saturated AlCl3-EMICl melts. The electrodeposits obtained at more negative potential than - 0.18 V versus Al(III)/Al in a LaCl3 saturated acidic melt (N = 0.667) were pure aluminum metal. It was suggested that lanthanum metal electrodeposits at around - 1.95 V in the LaCl3 saturated melt (N = 0.667) after addition of excessive LiCl and 50 mmol kg (-1) of SOCl2.