The purpose of the present study was to explore ESL students’ interactions in task-based synchronous computer-mediated communication (SCMC) in Second Life, a virtual environment by which users can interact through representational figures. I investigated Low-Intermediate and High-Intermediate ESL students’ interaction patterns before, during, and after three kinds of tasks, a Jigsaw task, a Decision-making task, and a Discussion task. The findings were that the Low and High-Intermediate ESL students engaged in several forms of interaction during the pre- and post-task periods in Second Life, such as checking their voice chat function, checking members, moving their avatars, and closings. These activities pointed to the nature of Second Life voice chat interaction as preconditions for further conversation, and for closing their conversation. Official task period activities revealed factors for task success, such as a leader, a structured way of approaching a task, no technical problem, and establishing a sense of telepresence (Schroeder, 2002) before the task. Concerning negotiation of meaning, the High-Intermediate students made more negotiation during the Decision-making tasks than the Jigsaw tasks, caused mainly by lexical meanings. The wrong answer team and the incomplete team engaged in more negotiations than the correct answer team and the complete team. However, the Low-Intermediate students in the complete team made more negotiations of meaning than the incomplete team. Both levels of students had fewer negotiations during the Discussion task than in the Jigsaw and Decision-making tasks, and they used comprehension checks, confirmation checks, and clarification requests as strategies for negotiation, overwhelmingly focused on meaning rather than form. The students played with their avatars more often during the Discussion task session than during the Jigsaw or Decision-making tasks, and their use of avatars seemed simply to be for fun, although another way explaining what students were doing is to recognize that they were also exploring the affordances of Second Life. Generally, the Low-Intermediate students had a positive attitude toward their learning experience in Second Life, whereas the High-Intermediate students expressed a more neutral view of their experience in Second Life. / text