A novel silicon microfabricated chemical reactor has been developed for testing catalyst particles relevant to chemical process applications.  The reactor incorporates a cross-flow design with a short pass multiple flow-channel geometry enabled by microfabrication technology.  The cross-flow geometry minimizes pressure drop though the particle bed and yields reaction conditions desirable for the extraction of chemical kinetics.  Flow distribution is achieved through an array of 256 shallow pressure drop channels that minimize the influence of the catalyst packing on the flow in the reactor.  Combined experiments and modeling confirm the even distribution of flow across the wide catalyst bed with a pressure drop ~ 1600 times smaller than typical microfabricated packed-bed configurations.  Coupled with the inherent heat and mass catalyst bed free of transport limitations, is an advantageous design for catalyst testing.  Kinetic studies with carbon monoxid oxidation as a model reaction demonstrates the usefulness of the microreactor for testing catalysts.  When instrumented with sensors, the silicon cross-flow microreactor provides the opportunity for parallel, high-throughput testing of heterogeneous catalysts.