Computer-Aided Software Engineering (also known as CASE) is the domain of software tools which is used to design and implement applications. The CASE tools are similar to and partly inspired by Computer Aided Design tools used to design hardware products. These are the tools are used to develop software which is high quality, defect-free, and maintainable. CASE software is software related with methodologies for the development of information systems together with automated tools that can be used in the software development process. In this paper, they are going to study about what are case tools, their history, uses and its various applications.