Termination rate coeffs., kt, of alkyl acrylate and alkyl methacrylate bulk homopolymns. At 40°C and pressures of 1000 and 2000 bar have been measured up to high degrees of monomer conversion using the time-resolved single-pulse-pulsed-laser polymn. (SP-PLP) technique. The chain-length dependence of kt has been deduced from SP-PLP data by adopting the power-law model kt = k0ti-a, where i is the chain length. For methacrylates at low degrees of monomer conversion, a is close to the theor. predicted value of 0.16. At conversions above 20% the exponent a increases significantly with increasing conversion. This effect becomes particularly pronounced in the gel effect region, where a, e.g. for MMA reaches values close to unity. In the case of acrylates with small alkyl ester side chains, such as Me acrylate, a is also close to 0.16 at low conversions and increases toward higher conversions. In the case of acrylates with larger alkyl ester side chains, such as dodecyl acrylate and 2-ethylhexyl acrylate, however, a is close to 0.4 even at low degrees of monomer conversion. The latter effect is strongly indicative of intramol. chain transfer, which generates significant amts. of midchain radicals in the system. The fact that such transfer processes take place is supported by SP-PLP data on alkyl acrylates polymd. in supercrit. carbon dioxide.