Power system planners and operators try to accurately model loads in order to analyze their systems, since loads have a significant impact on the system. However, it is very difficult to exactly describe loads in a mathematical model. There are two basic methods used for load modeling: the component based method and the measurement based method. The former is based on the load components at the bus; the latter is based on measurements from the power system. There are two important factors in load modeling. One is in the determination of the mathematical model that represents the load characteristics. The other is in the estimation of the parameters of the determined mathematical model. The composite load model is addressed in this paper. It has both static and dynamic load characteristics. The ZIP model and the induction motor model are used for the static and dynamic load models, respectively. In this paper, we describe the parameter estimations needed for the determined load model. The measurements are obtained using the TSAT simulation program. The parameter estimation is then verified using these measurements.