The problems of research into communicative language teaching are a special case of the problems facing research into any kind of foreign language pedagogy. They also overlap to a considerable degree with those facing any research in teaching, regardless of subject matter. This article reviews a range of research approaches which have been, or might be, used in researching various dimensions of communicative language teaching. It draws on the general literature on educational research methods to some extent, and on the general language pedagogy research literature, as well as on the growing body of research literature on communicative language teaching. This is not an exhaustive survey, however; instead, a limited number of studies are chosen for discussion so as to exemplify the major research problems and approaches.