The introduction of new antipsychotics has resulted in the availability of drugs with improved safety and tolerability as well as proven efficacy compared to the older antipsychotics. New compounds might show new or different adverse effects that arise in the post-marketing phase when a greater number of patients are treated. One goal of the drug safety program in psychiatry AMSP ( Arzneimittelsicherheit in der Psychiatrie) is the detection and description of severe, new, or rare adverse drug reactions (ADRs). Between 1993 and 2000, 122,562 patients were monitored in 35 psychiatric institutions, 86,349 patients of which received antipsychotics. Hyperglycemia related to antipsychotics was observed in association with only two compounds so far: clozapine and olanzapine (clozapine 2 cases, olanzapine 7 cases). In 6 of 9 patients, weight gain preceded hyperglycemia. The relative frequency of these adverse drug related events was 0.013 % for clozapine and 0.075 % for olanzapine. The symptomatology included reversible hyperglycemia, worsening of existing diabetes, and new-onset diabetes. Control for glycemic dysregulation should be maintained in clinical practice with these drugs.