The invention relates to a process for tightly controlling the particle size of cinacalcet hydrochloride, i.e. a process for preparing large or small crystals of cinacalcet hydrochloride, which yields cinacalcet hydrochloride in a narrow, reproducible and consistent distribution of particles, which hence does not require to reprocess, rework or destroy material of undesired size, which is efficient and cost-effective, and which is suitable for industrial implementation.
