A simple preparative method is presented to separate mixtures of isotactic and syndiotactic poly(methyl methacrylale) (PMMA) into components. The principle of this separation method consists in competitive adsorption of two different tactic polymers from solution onto a solid surface. Separation experiments were carried out at 25°C by using nonporous silica gel, Cab-0-Sil, as the adsorbent in chloroform, in which a stereocomplex formation between isotactic and syndiotactic PMMA does not usually occur. Some crystallizable PMMA, designated by Fox, et al., as type-III polymers, were successfully separated into components on a preparative scale by using this method. The result is discussed in terms of the microstructure of these polymer samples. KEY WORDS Competitive Adsorption 1 Polymer Separation Poly(methyl methacrylate) I Stereocomplex I Stereoblock I