The rate of mortality of the zebra mussel in response to chlorine is described by a kinetic model that combines a statistical characterization of mussel mortality with a disinfection-type modeling approach. Parameters estimates were made with nine sets of data from experiments conducted in Niagara River water. From the kinetic model, an operational diagram was constructed that describes the time to 95 percent mortality as a function of chlorine concentration and temperature. Either the model or the diagram can be used to assist utilities in planning chlorination treatments for controlling zebra mussels. Includes 19 references, tables, figures.