A new compound 2-(3,5-di-tert-butyl-2-hydroxyphenyl)-2-(3,4-dimethylphenyl) acetic acid dimethylamine salt ([NH2(CH3)2][C24H31O3]) was synthesized and structurally de- termined. It is of monoclinic system, space group P21/c with a = 14.731(2), b = 10.1185(10), c = 17.065(2) , β = 98.293(10)°, Z = 4, V = 2517.0(6) 3, Dc = 1.091 g/cm3, F(000) = 904 and Mr = 413.58. The dihedral angle defined by two benzene rings is 98.23°.