The radical telomerization of isopropyl (IPMA) and t-butyl (TBMA) methacrylates was carried out using bromotrichloromethane as a telogen at 50, 70, and 90°C, and compared with that of ethyl methacrylate (EMA). The telomerization behavior of these monomers and reactivity of the resulting telomers were greatly dependent on the kinds of alkyl substituents in the ester groups. The average degree of telomerization decreased, whereas the yield of lactones increased, with increasing degree of branching in the alkyl chain. The telomerization of IPMA gave the syndiotactic (st) dimeric telomer in preference to the isotactic one in a ratio around 85: 15, which was almost identical with the value in the telomerization of EMA. In the telomerization of TBMA, however, all the dimeric telomer which was produced at reaction temperature below 70°C, was the st one. Furthermore, the formation of carboxylic acid compounds was observed only in the telomerization of TBMA. The lactonization of dimeric-and trimeric-telomers was induced by the catalytic action of silica gel and heat. The IPMA telomers resembled EMA ones in the reactivities of lactonization. On the other hand, the TBMA telomers were greatly subject to lactonization in comparison with others. Lactones resulting from the TBMA telomers were further transformed into corresponding carboxylic acids. The carboxylation of TBMA lactones was promoted by the catalytic action of t-butyl bromide.