1. A series of 110 patients on whom transorbital leucotomy was performed is reported.2. These consisted of schizophrenia 74 cases, psychoneuroses 19 cases, affective psychoses 14 cases, paranoid psychosis 2 cases, mental deficiency with paranoia 1 case.3. The schizophrenic group had received the present-day accepted forms of treatment without relief and were considered non-salvageable, but showed a 53% improvement rate following transorbital leucotomy.4. Catatonic and paranoid types of schizophrenia responded most favorably in this category with a 74% and 63% improvement rate respectively, whereas the deteriorating forms showed a low improvement rate of 17%. If agitation was a significant feature of the deteriorated type, improvement was obtained after transorbital leucotomy.5. Among the obsessive-compulsive patients, previously subjected to psychotherapeutic techniques, ECT, etc., transorbital leucotomy effected an improvement in 84%. Improvement was slow initially but showed increasing momentum with the passage of time.6. Psychoneurotics with pronounced hypochondriacal preoccupations are not favorably influenced by transorbital leucotomy.7. The affective psychoses, wherein repeated courses of shock therapy have failed to prevent frequent recurrences, particularly agitated depressions, respond very favorably to transorbital leucotomy, an improvement rate of 83% appearing in the manic-depressives, and 63% in the involutional depressions.8. In view of the relative ease of performance, short hospitalization, minimal nursing care, insignificant morbidity, low mortality compared with other psychosurgical procedures, and the favorable results, the authors suggest that this procedure be utilized more widely in suitable cases before relegating them to custodial institutions for life, or permitting them to lead a burdensome existence.