There is growing attention to incorporating computer-mediated instruction for language learning and teaching. Specifically, vocabulary is arguably the foundation of mastering a language, as the mastery of vocabulary is the fundamental step of learning a language. Second language (L2) vocabulary is important in the development of cognitive systems of knowledge (Coady & Huckin, 1997). Previous studies on L2 vocabulary acquisition have focused on a wide range of methods to facilitate the acquisition of L2 vocabulary ranging from traditional instruction, such as dictionary use, to games and multimedia learning. Because it is difficult to draw firm conclusions from studies on different language skills, a systematic synthesis of research findings related to one particular language skill may provide more insight on the impacts of technology use (Felix, 2005). The study presented in this paper investigates the general effectiveness of L2 computer-assisted vocabulary instruction, with analysis of the features of treatment duration, educational level, the use of games and the role of teachers in the CALL studies. (Contains 2 tables.)