Various organizations increasingly adopt open source software, both on desktop PCs and servers. Since the first movements in open source in the 1960’s its growth has lead to new approaches in software development, licensing, and distribution, as well as in software vendors’ business models. The literature includes very interesting studies regarding prospective benefits, business models and case studies. However, the adoption of open source in large, global companies and its relationship with factors such as profitability, revenues and industry sector has not yet been researched. This study aims to answer these questions based on data we collected from Fortune 1000 companies and provides a method that can be applied in similar contexts.