This paper shows an object-oriented reengineering process of procedural legacy systems for Web-based environments. Thus, the architecture of these systems should be restructured for the client/server model. It can be made by separating the application logic and database components, which are executed in the server, from a user interface component, which is executed at the client. A middleware should be defined to be responsible for communication between these components. The reengineering proposed here uses the Fusion/RE method for the reverse engineering process. This method was specialized for COBOL language domain and guidelines are presented to generate an object oriented analysis model specified in UML. HTML language is used for the implementation of system?s new interfaces and the servlets, an API of Java language for the middleware. Persistence Layer design pattern is used to separate the application logic component from database component. These guidelines had been implemented in FAROOL tool, but this will not be focused in this paper