THE MAJOR THERAPEUTIC TRENDS: The treatment of psychosis in late life depends on the etiology of the delusion but also on its behavioral consequences (agitation, aggressiveness). We distinguish between the treatment of long term old psychosis and delusions occurring late in life (after the age of 60). FOR THE OLD PSYCHOSES: The reduction in the symptomatology often permits a reduction in the doses and the relay to atypical neuroleptics with improved tolerance. FOR DELUSIONS OCCURRING LATE IN LIFE: The treatment will be adjusted to the etiology of the delusion: delirious states associated with dementia, thymus delusion, schizophrenic or non-schizophrenic psychosis, delusion related to cerebral-vascular disorders or to sensorial dysafferentation. One should note that emotional and delusional disorders are often concomitant in the elderly. THE TWO TREATMENT AXES: The first therapeutic element is non-pharmacological: reassurance or even brief psychotherapy, family counseling and prevention of enhancing, notably environmental, factors. The pharmacological element preferably includes atypical anti-psychotics, antidepressants in some cases together with anti-epileptics in cases of concomitant rebellious aggressiveness. In cases of dementia with cholinergic deficiency (Alzheimer, Lewy body dementia, mixed dementia) cholinesterase inhibitors have demonstrated their efficacy on the hallucinations. Advice for a pertinent strategy of action should be provided.