The first step towards Research and Innovation for Gender Equity in Engineering is to conduct a gap diagnosis to outline the baseline. This article presents the methodology developed by the CAL Matilda research committee to create a gender gap diagnostic tool in Latin American engineering faculties. The methodology is based on a collaborative approach. The tool consists of 11 indicators that assess gender equity in four institutional groups: administrative staff, faculty, students, and researchers. It also investigates the existence of 5 programs and policies aimed at promoting equal rights and opportunities without gender discrimination. The data collection process faced challenges, such as segregating information by engineering programs and disruptions caused by the COVID-19 pandemic. Initial results highlight significant gender gaps in several engineering programs, especially in systems engineering and mechanical engineering, emphasizing the need to address horizontal segregation in this field and the necessity for differentiated strategies.This work establishes the foundation for evaluating the gender gap in engineering faculties in Latin America.