A three-layer neural network implemented by optical and electronic techniques for pattern recognition is described. The principle, the architecture, and the experimental results of the hardware system for pattern recognition are presented. A multiplex hologram is used as the interconnections between neurons of the input layer and the middle layer. The winner-take-all (WTA) operation of the intermediate layer is performed by an electronic circuit. The interconnection between neurons of the middle layer and the output layer is simply implemented with an optical transparency. By changing the patterns on the transparency, this system can be used for both auto- or heteroassociative memories. In addition to noise and partial hindrance tolerances, it also has illuminance invariance because of the WTA layer of the system.