We studied the possibility of using liposomal forms of hydroxyaluminium tetra-3-phenylthiophthalocyanine as a near infrared band photosensitizer. Experiments on mice with solid Ehrlich tumor and subcutaneously transplanted P-388 leukemia revealed high selectivity of accumulation of the photosensitizer in tumors in comparison with normal tissues and high photodynamic activity of the preparation. This photosensitizer can be used as the basis for creating an effective preparation for photodynamic therapy and fluorescent diagnosis.