Deep learning concept is totally based on artificial neural network concept. Much of unstructured data can be handled with help of deep learning. It also make use of many mathematical algorithms that can work on data and further analyze data. This chapter mainly describes various deep learning methods used in processing data in various applications. Beside of deep learning methods this chapter also elaborates importance of deep learning in various applications. Deep learning concept can be combined with big data and cloud computing concept to enhance its capability in various applications