The aim of this study is to develop an expert system for the diagnosis of diabetic patients. PIMA Indian Diabetes Dataset is used by the proposed system. The proposed system uses feature reduction techniques like Recursive feature elimination and principal component analysis for enhancing the performance. The expert system is built using Deep Neural Networks and Artificial Neural Networks. This study also compares the performance of proposed deep neural network with artificial neural networks using various performance measures: accuracy, sensitivity, specificity. © IAEME Publication.