By using a confocal laser scanning microscope and a digital image analyzer; the influence of a glass-suspension interface on colloidal crystals was studied. Particular attention was paid to the interparticle distance (2 D expt ) in the ordered structure and the crystallization process. The 2 D expt was insensitive to the distance from the interface up to about 40 μm. The crystallization process of the ordered structure was characterized by a strong anisotropy originating at the glass-suspension interface.