Six corn. anticaking agents were added in aq. solns. to MgSO(4)center dot 7H(2)O and Mg(NO(3))(2)center dot 6H(2)O crystals at 40 degrees C. After removal of H(2)O by evapn., the salts were thermostated under pressure and changing temp. (20-40 degrees C) for 24 h as cones. The disintegrating force was the measure of the caking ability. The org. sulfonates and amines were the most efficient anticaking agents.