Perversion had been viewed as oedipally determined and in a reciprocal relationship with neurosis. In our widening scope, however, pre-oedipal and traumatic contributions have been increasingly emphasized. While both perspectives represent aspects of clinical reality, the tendency has been to overlook sexual and aggressive drive derivatives, with their related conflicts, object representations, and symbolic enactments, even though they may make significant contributions to the analytic situation. These latter, ‘classical’ patients have what I consider ‘organized’ perversions: complex, evolved, neurotic-level, stable psychopathological formations that may be distinguished from borderline or near psychotic syndromes enlisting perverse mechanisms to ward off disorganization. This paper will review Freud’s work, briefly consider some recent trends in conceptualizing perversion and perverse mechanisms, characterize organized perversion, and present clinical material to illustrate its evolution, clinical manifestations, and analysis. Transsexualism, overtly similar to transvestism but not functioning as an organized perversion, will serve as a point of contrast.