This mixed-methods study looks at patterns of emoticon usage in adult, ESL student writing. Data are drawn from 13 students and their participation in online discussion forums designed to supplement a traditional ESL writing course. The study conceptualizes computer mediated communication as a hybridized and emergent form which utilizes features of both oral and written discourse. Emoticons are seen as central to this hybridity in terms of their ability to serve as textual representations of oral discourse features. Findings from this study suggest that emoticon usage is prevalent in the writing of some non-native speakers of English but that usage patterns vary significantly across individuals. Previous experience with discussion forums in the first language as well as emoticon familiarity are identified as mediating factors in emoticon usage in English. The study also raises concerns about the multiple interpretations of emoticons and the possibilities for miscommunication and misunderstanding. (Contains 8 tables and 1 note.)