There is disclosed a process for the separation of long chain dibasic acid and fatty acid, comprising: (1) reacting a mixture of long chain dibasic acid and fatty acid with ammonium hydroxide to form an insoluble ammonium salt of fatty acid and a soluble ammonium salt of long chain dibasic acid; (2) recovering the insoluble ammonium salt of fatty acid; and (3) adding an acid to the mother liquor of step (2) to obtain the long chain dibasic acid.