The invention relates to a novel crystallisation process for preparing fluticasone propionate as crystalline form 1 polymorph with controlled particle size and suitable for micronisation. Said process comprises the step of dissolving fluticasone propionate in acetone or in a mixture of acetone and water and then adding this solution to water or to a mixture of water 10 and acetone, thereby causing fluticasone propionate to crystallise out of the solution as crystalline form
