A kinetic model that accurately describes intensity vs. time reaction profiles for the chemiluminescence reaction between luminol and hydrogen peroxide, as catalyzed by horseradish peroxidase, is derived and evaluated. A set of three differential equations is derived and solved to provide intensity time information for the first 200 seconds of the reaction. The model accurately predicts intensity-time profiles when literature values are used for all but one of the reaction rate constants. Furthermore, the model predicts a nonlinear curve for plots of light intensity versus the initial hydrogen peroxide concentration. Experimental data confirm that such plots are nonlinear. Finally, a linear double-reciprocal plot is predicted by the model and the experimental data verify this relationship.