A novel procedure is outlined by which the termination rate coefficient, k(t), may be deduced from molecular weight and monomer conversion data of pulsed laser polymerization (PLP) - size exclusion chromatography (SEC) experiments. For this k(t) analysis only the central part of the molecular weight distribution (MWD) between the first point of inflection (POI), that is also used for k(p) analysis, and the third such POI is taken into account. Within this region a characteristic ratio of areas under the MWD is fitted either by using PREDICI or by applying a lumping scheme method. The success of the lumping scheme procedure is demonstrated for the bulk polymerization of butyl methacrylate. The k(t) values derived by this method refer to small initial degrees of monomer conversion as are typical of PLP-SEC investigations. The relatively fast and efficient lumping scheme technique is restricted to situations where k(t) may be considered independent of chain length and where chain transfer processes are not important.