Requirements elicitation is one of the fundamental activities to finding and understanding the required functionality and user needs. This article presents a technique for requirements elicitation from legacy systems applying Reverse Engineering to its Graphical User Interfaces (GUIs). The technique looks at the components of the GUI, the interface language and design patterns, answers about the functionality of the legacy application, making it a useful tool for the analyst when obtaining prior domain knowledge and the user needs. This article presents a technique called ReFRee (Reverse Engineering Requirements for Elicitation) using two examples of application. For both cases, there is not access to its source, data or information about its design and construction. What is interesting is that despite the completely different nature of application domains, the graphical interfaces analysis yields the promising results regarding the recovered functional requirements.