A novel crystalline polymorphic form of ulipristal acetate useful as an agent for preventing and/or treating uterine leiomyoma and as a contraceptive, and a process for producing the crystalline polymorphic form are provided. The novel crystalline polymorphic form of ulipristal acetate is obtained by dissolving an isopropanol-solvated crystal of ulipristal acetate in a mixed solvent containing ethanol and water, and crystallizing an ulipristal acetate from the solution without addition of a seed crystal to the solution.本發明提供可用作用於預防及/或治療子宮平滑肌瘤之藥劑及用作避孕劑之烏普司他醋酸(ulipristal acetate)之新穎結晶多晶型及產生該結晶多晶型的方法。烏普司他醋酸之該新穎結晶多晶型係藉由以下方式獲得:將烏普司他醋酸之異丙醇溶劑化晶體溶於含有乙醇及水之混合溶劑中,且在不向溶液中添加種晶下使烏普司他醋酸自該溶液結晶。