Mifepristone substantially in polymorph form M is provided. Also provided is a process for the preparation of polymorph form M of mifepristone comprising the steps of (a) dissolving crude mifepristone in a polar solvent at an elevated temperature to obtain a clear solution; (b) cooling the solution to a temperature and for a time period sufficient to form a precipitate of mifepristone crystals; and (c) isolating the precipitate of mifepristone crystals to obtain the polymorph form M of mifepristone.