The copolymerization of 3,3,3-trifluoro-1,2-epoxypropane (TFEP) with 1,2-epoxypropane (EP) using organozinc compounds, [Zn(OMe)(2)(EtZnOMe)(6)], [Zn(OMe)(2)](n), and Et(2)Zn-H2O (1:0.8), was studied. The molar ratio of TFEP and EP in the resulting copolymer was estimated by H-1-NMR analysis and elemental analysis. The copolymerization that started with equimolar amounts of TFEP and EP produced an EP-rich copolymer in moderate yield when [Zn(OMe)(2)(EtZnOMe)(6)] or [Zn(OMe)(2)](n) was used as the initiator. On the other hand, copolymerization initiated using Et(2)Zn-H2O (1:0.8) produced TFEP-EP copolymers with various molar ratios in high yield. H-1-NMR and DSC analyses indicated that the copolymerization proceeded in a block manner. When the molar ratio of TFEP in the copolymer obtained using [Zn(OMe)(2)(EtZnOMe)(6)] approached approximately 90%, the T-m, T-g, and contact angle to water of the copolymer were close to those of the TFEP homopolymer.