In second language (L2) writing classrooms, prewriting discussions are one of the most commonly used collaborative activities (Fernández Dobao, 2012, Storch, 2005), yet there has been little research about their relationship to students' written texts. Recent L2 writing research has examined the textual features of co-constructed texts (e.g., Elola and Oskoz, 2010, Kuiken and Vedder, 2002, Storch and Wigglesworth, 2007), whereas the pretask planning literature has focused mainly on the effect of individual planning (e.g., Ellis and Yuan, 2004, Kroll, 1990, Ojima, 2006). The current study investigates the relationship between interaction during collaborative prewriting tasks and students' written texts in an English for academic purposes (EAP) course. The findings indicate that structured collaborative prewriting tasks elicited student talk about content and organization, but there is only a moderate relationships between these prewriting discussions and the students' written texts. Implications for the use of collaborative prewriting discussions in EAP contexts are discussed.