In Korea, elderly population aged 65 and older are about 5.0% and 10.7% in 1990 and 2009, respectively. Since elderly people may experience physiologic changes with aging and their pharmacodynamic and pharmcokinetic parameters also have been undergone changes, several adverse drug reactions can occur more frequently than young people. Especially, neuropsychiatric adverse drug reactions such as delirium and drowsiness endanger elderly patients more. The purpose of this study is to evaluate the outpatient prescriptions using drug causing delirium and drowsiness in elderly patients aged 65 and older. We retrospectively reviewed prescriptions for elderly patients collected from four community pharmacies from January 2nd to February 1st, 2010. One pharmacy was located closed to a general hospital, and others were located closed to a internal medicine or an ENT clinic. The each number of the collected prescriptions was followings; Group A (n=496) from internal medicine department of a general hospital; Group B (n=44) from ENT department of general hospital; Group C (n=144) from internal medicine clinic; Group D (n=110) from ENT clinic. In result, in Group A, the average number of prescribed drugs causing delirium or drowsiness per Rx was 2.38 In Group B, the average number of prescribed drugs causing delirium or drowsiness per Rx was 2.09 In Group C, the average number of prescribed drugs causing delirium or drowsiness per Rx was 2.51. In Group D, the average number of prescribed drugs causing delirium or drowsiness per Rx was 2.72. Especially, in Group D, the percentage of prescription that drugs causing delirium or drowsiness per Rx prescribed more than 3 is 52.73% In all the 4 groups, over the 60% of drugs causing delirium and/or drowsiness per prescription of elderly patients were prescribed. It means elderly patients take 2 drugs causing delirium and/or drowsiness among 3 drugs, which is very serious. Frequently prescribed drugs causing delirium and/or drowsiness were followings; GI agents, antitussives & expectorants, histamine H1 antagonist, analgesics, antibiotics. Among these drugs, GI agents was high raking in all the 4 groups, and pharmacists should caution elderly patients when counseling. In the internal medicine groups (Group A,C), drugs concerning chronic diseases were prescribed frequently. In conclusion, pharmacist's role is important. Pharmacists are well informed of the drugs causing delirium or drowsiness and it is important to explain about ADRs slowly and easily to the elderly patients that receive drugs causing delirium or drowsiness. And institutional device is needed. For example, when doctors prescribe drugs for the elderly patients, message is needed that supply some informations about drugs causing delirium or drowsiness.