Tetrachlorophthalic acid has been used as a precipitant for the determinations of thorium^[1] and zirconium^[2].These two metals precipitate at rather high acidifies.Recently, the solubility products of thorium, lanthanum, praseodymium, and neodymium tetra-chlorophthalates have been reported^[3].It is interesting to note that Crookes^[4] already prepared scandium tetrachlorophthalate in 1910.These facts lead us to study the said acid as a reagent for scandium and its separation from thorium.It is found that scandium precipitates quantitatively with tetrachlorophthalic acid in the pH range of 2.4-4.4 (cf.Table 1^*), whilst thorium in pH 1.0-1.1^[1].Hence, there exists the possibility of separating these two elements simply by adjusting the acidity of the solution, which has been substantiated experimentally in this communication.