The present invention relates to crystalline forms of cabozantinib phosphoric acid salt and cabozantinib hydrochloric acid salt and to a method for their preparation. Furthermore, the invention relates to pharmaceutical compositions comprising said crystalline forms and their use as anti-cancer medicaments. Cabozantinib, i.e. N-{4-[(6,7-dimethoxy-4-quinolinyl)oxy]phenyl}-N′-(4-fluorophenyl)-1,1-cyclopropanedicarboxamide is represented by the chemical structure: Formula.