The free-radical copolymerization of ethene (E) and methyl acrylate (MA) is studied between 220 and 290 degrees C at 2000 bar. The reactions which have been induced thermally are carried out in a continuously operated device at total monomer conversions mostly below 1%. Monomer concentrations are obtained from measured mass fluxes. Copolymer composition is determined via elemental analysis. Reactivity ratio data, r(E) and r(MA), are derived from non-linear least squares fitting of the monomer mixture and copolymer compositions. r(E) and r(MA), e.g., at 220 degrees C and 2000 bar, are found to be 0,045 +/- 0,002 and 5,3 +/- 0,2, respectively. The r(E) and r(MA) values slightly, but significantly, differ from corresponding data for ethene-butyl acrylate (BA) and ethene-2-ethylhexyl acrylate (EHA) copolymerizations. Toward higher temperature r(E) increases and the acrylate (MA, BA, EHA) reactivity ratio r,decreases. The temperature dependences of r(E) and r(A) can not be distinguished for the three ethene-acrylate systems. From an experiment at two levels of polymerization pressure, 1500 and 2000 bar, the pressure dependence of r(E) has been estimated. The available data for r(E) and r(A) allow to model monomer concentration vs. polymer composition behavior of free-radical ethene-acrylate copolymerizations at technically relevant temperatures and pressures.