For the active pharmaceutical ingredient used in the treatment of schizophrenia, olanzapine, it was necessary to find the solvent which is most suitable in the form of the morphology of the crystals obtained. Crystallization was performed with isobutyl acetate, methyl isobutyl ketone, ethyl acetate and toluene as solvent. The research was conducted in a batch crystallizer. Due to the better crystal morphology and solubility curve, toluene was chosen as the most suitable solvent, and further crystallization research was carried out in toluene. In this work, the effect of the type of mixer on the morphology and granulometric properties of crystals was investigated. Four different mixers were used, of which two mixers achieve axial flow and two radial flow. Also, the effect of the stirrer speed on the properties of the obtained crystals was investigated. The study was conducted at 150, 250, and 350 rotations per minute. In order to characterize the obtained olanzapine crystals under different process conditions, the chemical composition was analyzed by X-ray diffraction, granulometric properties were also analyzed by measuring particle size distribution using laser diffraction method and FBRM probe, and crystal morphology was analyzed by optical and scanning electron microscope with different magnifications. The thermal properties of olanzapine crystals were investigated by differential scanning calorimeter and with thermogravimetric analysis.