OBJECTIVE The study was to evaluate objectively (by a physician) and subjectively (by the patients) the efficacy of 12-months olanzapine treatment of schizophrenic out-patients. METHODS Olanzapine treatment was either initiated or patients were switched from other antipsychotics to olanzapine. Patients' subjective evaluation with the use of SWN and DAI scales was compared with physicians' objective evaluation with the use of PANSS, CDS and CGI scales. RESULTS The treatment with olanzapine caused significant improvement of schizophrenia positive, negative and affective symptoms. The use of the DAI questionnaire revealed also subjective improvement after olanzapine treatment. The decrease of schizophrenic symptoms correlated with the improvement of patients' subjective feeling of self-control, psychic functioning and somatic health. No serious adverse events were seen during the treatment. The severity of adverse events decreased during the olanzapine treatment. CONCLUSIONS Olanzapine treatment of patients suffering from schizophrenia proved to be efficacious in both objective and subjective evaluation.