Control chart pattern recognition is an important aspect of statistical process control(SPC). The presence of unnatural patterns indicates that a process is affected by assignable causes, and corrective actions should be taken. This paper describes one type of pattern recognition procedure based on modural neural network architectures. The pattern recognition procedure were developed to take the advantage of the fact that a particular unnatural pattern is often associated with a set of assignable causes. Th e performances of the proposed pattern recognition procedure were evaluated through Monte Carlo simulations on the basis of appropriate performance measures. An extensive evaluation indicates that the proposed pattern recognition procedure could recgnize multiple unnatural patterns for which they were trained. The results also indicat that modular network performance is batter than that of backpropagation neural network.