The core-first synthesis of three-, four-, and six-armed star-shaped poly(methyl methacrylate)s (PMMAs) with predicted molecular weights and narrow molecular weight distributions (M(w)/M(n)s) was carried out by the t-BuP(4)-catalyzed group transfer polymerization (GTP) of methyl methacrylate (MMA) using the newly designed silyl enolates, such as 1,1,1-tris[2-methyl-1-(trimethylsilyloxy)prop-1-enyloxymethyl]propane (E(C(MTS)(3)), tetrakis{[2-niethyl-1-(trimethylsilyloxy)prop-1-enyloxy]methyl}methane (C(MTS)(4)), and bis{2,2,2-tris[2,methyl-1-(trimethylsilyloxy)prop-1-enyloxy]ethyl}ether (O-(C(MTS)(3))(2)), respectively. The absolute molecular weight (M(w)(MALS)) of the obtained polymers proportionally increased with the increasing [MMA](0)/[initiator](0) ratio, and the highest molecular weight was ca. 132 kg mol(-1). Characterizations for the star-shaped PMMAs were conducted by cleavage and intrinsic viscosity [eta] experiments. Cleavage experiments of the star-shaped PMMAs provided the evidence for homogeneous growth of the each arm in the t-Bu-P(4)-catalyzed GTP. The number of arm determined from the shrinking factors (g') of [eta] also supported the successful syntheses of the star-shaped polymers by the present core-first method. The versatility of this core-first method toward other methacrylic monomers was confirmed by the t-BuP4-catalyzed GTPs of allyl methacrylate (AMA), stearyl methacrylate (SMA), and 2-(dimethylamino)ethyl methacrylate (DMAEMA) using C(MTS)(4) as an initiator leading to well-defined star-shaped polymers.