A process for the preparation of crystalline oxytitanium phthalocyanine showing a distinct diffraction in peak at a Bragg angle (2.theta..+-.0.2.degree.) of 27.3.degree. in the X-ray diffraction spectrum, which comprises mechanically pulverizing oxytitanium phthalocyanine, dispersing it in water to form a suspension, adding an organic solvent into the suspension and heating the suspension.