A data acquisition system has been developed to collect, analyze and store large volumes of rapid kinetic data measured from a stopped-flow spectrophotometer. A digital minicomputer, with an A/D converter, tape drive unit and formatter, analog recorder, oscilloscope, and input/output terminal interfaced to the stopped-flow spectrophotometer provides the complete system. The user is directed through the initialization by a series of decision steps. The first step is to choose a data file, either existing or new. Once the desired file is selected, several options including data collection, analysis, storage, and printing are selectable. Ozone decomposition and the rapid reaction between ozone and cyclohexene in neutral solutions were studied using the data acquisition system.