Analysis of insight in obsessive-compulsive disorders (OCD) raises conceptual problems that need addressing before meaningful empirical work can be undertaken. Insight and OCD are locked within a definitional contradiction relevant both to the nosological boundaries of OCD and the meaning of insight itself. Given that it is a form of self-knowledge, it is proposed here that insight is best conceived as a mental state rather than symptom or symptom-dimension. As an aspect of this mental state, the clinical phenomenon of insight should be understood as independent of any underlying disease albeit influenced by it and by other factors. As the focus of empirical research, the phenomenon of insight is dependent on the concept of insight, the measure by which it is assessed and on the 'object' of insight assessment. Explication of these factors allows for the delineation of specific insight phenomena whose respective usefulness can be determined by empirical research.