The application of in vitro and in vivo ATP bioluminescence systems as an integrated approach for preclinical research and development of new chemotherapeutic drugs is described. This approach includes both (a) the in vitro tumor response assay (TRA) system that utilizes new technologies for cell culture and ATP measurement of clinical specimens and (b) the use of human tumor cell lines transfected with Photinus pyralis luciferase (luc) gene for both in vitro and in vivo studies. Dried reagent microplates for TRA culture and counting procedures are described for a two-stage TRA method, which can be used to evaluate drug sensitivity and resistance of cells from clinical specimens after initial drug exposure in vitro. The use of dried reagent counting plates for screening and testing of agents against tumor cell lines is described, as well as an alternative method for screening and testing chemotherapeutic drugs in vitro with luc-transfected human tumor cell lines. The potential application of luc-transfected reporter cell lines for in vivo studies of drug activity with photon imaging for analysis is discussed.