Bacteria are the most common agents that cause leprosy . Mycobacterium leprae is bacteria which cause this disease. Encephalitis is a complex and severe disease that can occur in people of all ages anywhere in the world. It is defined as an inflammation of brain substance together with evidence of brain. Drug discovery and development is a complex, high risk, time consuming and potentially highly rewarding process. The development of new drug requires a technological expertise, human resources and huge capital investment. Bioinformatics is a very useful field as it makes such tools which provide the full information about the proteins and gene families and in this work we use this information for targeting HSP70 protein which causes encephalitis and for prediction of drug target and drug discovery using various Software.