There is now a substantial body of research that has investigated the role of form-focused instruction in assisting learners to learn the grammar of a second language (L2). Recent comprehensive surveys of this research have been provided by N. Ellis (1995), R. Ellis (1990; 1994; 1997), Larsen-Freeman and Long (1991), Long (1988), Spada (1997), and Williams (1995a). However, it is becoming increasingly difficult to draw clear conclusions given the sheer amount of research now available, the problems of comparing results across studies, and the interactivity of the variables involved. Spada, for example, identifies seven questions that the research has addressed but acknowledges that “we do not yet have clear answers to any of these questions” (p. 74). One way of achieving a clearer understanding of how form-focused instruction contributes to acquisition might be to examine in detail studies that have investigated the effect of specific instructional options. This article will follow such an approach by examining one particular option–input–based grammar teaching.