The author systematises and examines the relation between theory and practice in psychoanalysis in three directions: one, eminently epistemological, which is only mentioned because it pertains not only to psychoanalysis but to all the sciences; another, the relation between theory and technique; and the third, the relation between theory and the institutional organisation of psychoanalysis and psychoanalysts. All the problems described, especially the second and third points, together define psychoanalytic praxis. With regard to contradictions between theory and technique, the author points out that psychoanalytic theory is constructed fundamentally on the basis of an approach that is historico-genetic, dynamic and consistent with formal logic, whereas psychoanalytic practice occurs within a transference-countertransference relation, in a situation configured as an analytic field, a 'here and now', within a dramatic explanation and in a dialectic process. This triple diagnosis involves naturalistic and phenomenological approaches, the problem of objectivity and the role given to sexuality as a privileged parameter in psychoanalytic theory. In relation to the third direction mentioned above, the author refers briefly to the problem of psychoanalytic organisations, in the sense that they come into conflict with the development of psychoanalytic theory and the deepening of investigation. In reference to the latter, the author emphasises the need to widen the perspective of what constitutes psychoanalytic praxis. He points out that praxis is always replete with contradictions and that it is not a question of ignoring, denying or impeding these contradictions themselves (which would in any case be totally ineffective), but that by taking them into account, scientific development could be managed in a more planned way, less blindly; that is to say, less abandoned to spontaneity.