The polymorphism of bicalutamide and the factors affecting its crystal formation have been studied. The standard forms of bicalutamide were prepared by evaporat ion and meltingcooling processes. Two crystalline forms of bicalutamide were o btained by antisolvent precipitation and their structures were determined by c omparing their X-ray powder diffraction patterns with those of the standard for ms. A range of mixed solvents were screened in order to determine the optimum sy stem. It was shown that changing the volume ratio of two solvents can induce cry stallization of different polymorphs. 