This study examines the effects of task familiarity through the use of subtitled videos on negotiation of meaning in an online task-based language learning (TBLL) environment. It explores the amount of negotiation of meaning produced by non-native speakers (NNSs) aimed at improving input comprehension to enhance second language acquisition. Ten NNS-NNS dyads collaboratively completed 4 communicative tasks using an online TBLL environment specifically designed for this study and a chat tool in WebCT-Vista. Five dyads were provided with subtitled videos prior to task completion; the remaining 5 dyads completed tasks without seeing the videos. The amount of negotiation of meaning was calculated via the negotiation of meaning sequences model developed by Gass and Varonis (1985) and revised for online communication by Smith (2003). The data from the chat-scripts showed that NNSs who were familiarized with tasks engaged in more negotiation of meaning as compared to their peers who were not. (Contains 7 figures and 4 tables.)