This study deals with the spherical crystallization process by the quasi-emulsion mechanism, applied to a pharmaceutical. The objective is to produce spherical agglomerates made of a number of small crystals of the drug, having properties adequate for direct compression when manufacturing tablets. The aim of this work is to make the link between the process and these properties. The different steps occurring in the process are the formation of an emulsion whose droplets are made of the drug dissolved in a solvent: the creation of the supersaturation of the drug in the droplets by mass and heat transfer and the nucleation, growth and agglomeration of drug crystals inside the droplets. The process has been carried out in a batch laboratory scale device. The variation of the operating parameters on the one hand and of the relative proportions of the various components on the other have enabled us to determine the influence on the internal and external structures of the produced agglomerates which influence the ability to be compressed. The identification of the phenomena occurring has led to a proposed mechanism for the formation of the agglomerates.