Advanced students at university level struggle with many aspects of academic writing in English as a foreign language. The purpose of this article is to report on an investigation aimed at analyzing what collaborative writing through project work tells us about students' academic writing development at the tertiary level. The compositions written by students before the implementation of our research project showed that their command of written English was weak in form and content. The findings suggest that students evidenced difficulties when using language structure and organization of ideas, plus their argumentation often deviates from the topic given.