Radical copolymerization of tetrafluoroethylene (TFE) with ethylene (E) by azo-bis-isobutyronitrile in the temperature interval 335-363 K, monomer pressure from 3.0 to 7.0 MPa at TFE/E molar ratio from 77/23 to 23/77 in bulk was carried out. The effect of reaction conditions on the yield, molecular weight, and polymer composition of copolymer synthesized was studied. White powdery alternating copolymers were obtained at TFE content in the monomer mixture from 65 to 85 mol %. Copolymerization rate R was described by the equation R = k(M)[ln][Sigma M](1.3) which was related to the heterophase character of the reaction. The reactivity ratio of TFE and E (0.067 +/- 0.12 and 0.52 +/- 0.18, respectively) and apparent activation energy E(a) = 135 kJ/mol were found. The TFE and E block formation probabilities were calculated and compared with IR spectroscopy data. Melting point, entropy, and enthalpy of fusion of the entirely alternating copolymers were determined. Some of the basic properties of the alternating copolymers obtained were also studied.