Radical copolymerization of tetrafluoroethylene (TFE) with ethylene (E) was initiated by 2,2’-azo-bis-isobutyronitrile in batch and semibatch operation. The effect of reaction conditions (temperature, pressure, stirring speed, molar ratio of monomers, etc.) on copolymerization rate and copolymer molecular weight was studied. The highest reaction rate was observed at TFE content over 70 mol % and was found to be proportional to initiator concentration and total monomer content by powers of 0.9 and 1.54, respectively. These dependencies were attributed to the heterophase character of the copolymerization. The monomer reactivity ratios and overall activation energy of the reaction were determined. The effect of the monomer composition on the distribution of monomer units in the copolymer chain was studied. Kinetic mechanism of the copolymerization was suggested. Some of the basic physical properties and chemical resistance of the alternating copolymers synthesized were also determined.