Highly isotactic-specific polymerization of methyl methacrylate (MMA) was developed by using a combined anionic initiator comprising alpha-lithioisobutyrate (Li-iPrIB) and a large excess of lithium trimethylsilanolate (Me3SiOLi), which afford, in particular, isotactic poly (methyl methacrylate) (PMMA) with isotactic triad content of up to 99.5% under the adjusted polymerization conditions. The polymerization system also exhibited a high activity such that isotactic PMMA with (M) over bar (n) of over 800 000 and narrow molecular weight distribution ((M) over bar (w) / (M) over bar (n) < 1.2) was obtained.