With the development of multidirectional education system, importance of libraries and information science has been increased. Not only traditional libraries have grown in size but a new concept of libraries called as digital library has come in to existence. Digital library has got lot of changes not only in the library and information services but also in the roles and expectations of the librarians and information professionals. Increase in technological explosion changes our lifestyle in few decades. Digital Library are playing a vital role for disseminating of information in modern society. Each and every library is slowly setting digitized. A digital library comprises digital collection, services and infrastructure to sport lifelong leering, research, scholarly communication as well as preservation and conservation of our recorded knowledge. In this paper we are focusing on the meaning digital library, needs, its advantage and challenges of digitization of library and the role of librarians in the digital libraries.