Effective and accurate health care has always been the need of the hour. Early detection of various diseases such as pneumonia, tumor, and cancer is very much essential. Pneumonia, an acute respiratory infection ranked eighth in the list of the top 10 causes of death in the United States [1]. According to WHO, it accounts for about 1.6 million deaths a year in this age group - 18% of all deaths among children under five [2]. The paper aims to automatically detect pneumonia using chest x-ray images. We prepared five different models and analyzed their performance and choose the best-suited model for developing Pneumonia Detection System. Five different pre-trained deep Convolutional Neural Network (CNN): VGG16, ResNet50, InceptionV3, InceptionResNetV2, and Xception network were used for transfer learning. VGG16 network performed well with better accuracy of 92% which is better than other CNNs.