This article identifies and explores some unresolved problems surrounding the role of theory and evidence in qualitative research. It begins by distinguishing among various meanings of the term theory, focusing in particular on the view that portrays it as consisting of specific explanatory principles. An ambivalence towards theory on the part of qualitative researchers is highlighted, showing how the influence of positivism persists despite explicit rejection of it. The problems involved in non-positivist reinterpretations are discussed, notably the attempt to integrate theory with description. The focus of the paper then turns to the concept of evidence. Here again a tendency for qualitative researchers to inherit an empiricist approach is identified, and the implications of abandoning it are outlined. Finally, it is argued that theory must not be seen as the only or even as the most important product of qualitative (or indeed of quantitative) research; several types of product are possible, each placing different requirements on the researcher.