Before the introduction of DSM-III, the Menninger Clinic diagnosed borderline personality on the basis of dynamic manifestations of splitting, denial, lack of sublimatory capacities, transient lapses of reality testing, problems of separation-individuation, and projective identification. The records of twenty-seven patients who had been so diagnosed were reviewed, and the cases rediagnosed according to DSM-III for borderline personality disorder. Twelve patients (44%) met these new criteria. Therefore, the authors conclude, the pre-DSM-III literature based on the Menninger patient population remains a potentially useful source of information on this condition.