The purpose of this work was to demonstrate that it is possible to determine the kinetics of biodegradation of single organic compounds by using only measurements of oxygen consumption in batch reactors. Batch experiments were conducted using acclimated biomass growing on aniline or benzoic acid in which simultaneous determinations over time were made of oxygen consumption, substrate removal (by SCOD, DOC and 14C) and cell growth. Kinetic parameters were estimated by applying nonlinear curve-fitting techniques to each of the data sets. There were no important differences between the parameter estimates determined from oxygen consumption data and any of the measurements of substrate removal. In general, parameter estimates made with cell growth data were the least reliable.