BACKGROUND: Dementia is a neuropsychiatric disorder characterized by cognitive impairments and behavioural and psychiatric symptoms. Various behavioural and psy- chological symptoms of dementia (BPSD) especially increase the burden to family and society. We studied the treatment efficacy and safety of risperidone and olanzapine on elderly dementia patients. METHODS: The study population consisted of 42 elderly patients who had BPSD with dementia, treated with risperi- done or olanzapine. Clinical safety and efficacy was evalu- ated by Clinical Global Impression (CGI) and side-effects checklist. Mean age was 68.2 ± 5.9 with 16 (38.1%) male and 26 (61.9%) female subjects. The types of dementia among the 42 demented patients were as follows: Alzheimer's dis- ease 25 (59.5%), vascular dementia 10 (23.8%), and other dementia 7 (16.7%). RESULTS: Mean Geriatric Dementia Scale scores was 5.5 ± 1.0. The efficacy of risperidone vs olanzapine was "markedly improved" 12.9% vs 34.0%, "moderately improved" 45.2% vs 29.9%, and "mildly improved" 32.2% vs 36.1% on CGI.The incidence of adverse reactions was 25.8% vs 36.4% respectively. CONCLUSIONS: Risperidone and olanzapine were found to be highly useful and well-tolerated antipsychotic drugs for behavioural and psychological symptoms of dementia between 1-2 mg vs 5-7.5 mg daily dosage respectively. However, proper evaluation of behave-ADAS (Alzheimer's Disease Assessment Scale), IADL (Instrumental Activity of Daily Living) and a larger number of elderly patients must be analyzed.