Pattern recognition can be done both in normal computers and neural networks. Neural networks may not perform miracles, but if constructed with the proper architecture and trained correctly with good data, they will give amazing results, not only in pattern recognition but also in other scientific and commercial applications.The significance and scope of neural network, which is simplified model of the biological neuron system, is a massively parallel distributed processing system made up of highly interconnected neural computing elements. That has the ability to learn and there by acquire knowledge and make it available for use. There are various types of neural network applications. Particularly for pattern recognition is the most popular application in neural network. Neural network is being used in manufacturing plants for controlling automated machines. Neural network historical background is important to under stand how ¿Artificial Neural Network¿s¿ (ANN¿s) architecture is developed and how the research going on. This book presents the conceptual study of pattern recognition by means of neural network and emphasized the NN as tool in Mechanical Engineering applications.