A mathematical model, consisting of six ordinary differential equations and taking into account the lateral interactions in the adlayer, has been developed for simulating the NO+H-2/Pt(100)-(1 x 1) reaction. This-model provides a good theoretical description of temperature programmed desorption and temperature programmed reaction (TPR) experiments, including the occurrence of a "surface explosion" in TPR studies. In addition, the model is capable of reproducing many kinds of nonlinear behavior observed in the experiments such as kinetic oscillations and the transition to chaos through period-doubling bifurcations followed by a period-3 or period-5 limit cycle. The simulation results suggest that the (1 X 1)double left right arrow hex surface phase transition of Pt(100) is not essential to describe the kinetic oscillations and chaos in the NO+H-2/Pt(100) system. The most important step in the oscillation mechanism is the autocatalytic increase in the number of vacant sites for NO dissociation.