Abstract: A wiki is a powerful online writing tool with revising and editing functions. Learners can participate, interact and collaborate on Wiki. These special functions of Wiki are claimed to be very useful for EFL students. Furthermore, it also has a function of providing a historical record of changes to the site. This function can be beneficial for teachers who evaluate the students and for researchers who assess the effectiveness of this online tool. Against this technological background, this is a report of the initial phase of a series of studies in which Wiki was introduced and implemented at an EFL class at a Japanese university. Specifically, the purpose of this study is to find the students’ perception of using wiki with regard to collaborative learning, satisfaction, motivation and the effectiveness in enhancing their writing skills. An integrated account of the results from quantitative and qualitative analyses will shed light on how wikis can be best employed in the EFL writing class.