OBJECTIVES To review the drug prescription pattern of antiulcerative agents for elderly inpatients. METHODS: The study population comprised inpatients of community hospitals who were members of the Korean Elderly Pharmacoepidemiologic Cohort (KEPEC), aged 65 years or over, beneficiaries of the Korea Medical Insurance Corporation (KMIC) and residing in Busan city in 1993. The drug prescription information was collected from the claims data of hospitals where the cohort members received medical care between January 1993 and December 1994. The information included personal identification, age, gender, diagnosis, drug dosage, date of hospital admission and name of medical institutions where the study subjects received drug prescriptions. The data analysis produced outcomes in terms of distribution of antiulcerative agents by class and by medical institution and trend of relative prescription. Analysis was also performed in terms of combined prescriptions of antiulceratives and drugs that could induce risk from drug interaction with antiulceratives. RESULTS: The number of patients prescribed antiulcerative agents was 1,059 (64.9%) male and 1,724 (65.5%) female among the total inpatients. An antacid and composite agent was the most frequently prescribed antiulcerative agent (70.8%), followed by H2 antagonist (16.0%). Among the potential drugs that could induce risk from drug interaction with the antiulcerative agents, diazepam was the most frequently prescribed. The proportion of diazepam co-prescription was 22.5% of the total cimetidine prescriptions and 14.5% of the total omeprazole prescriptions. CONCLUSIONS: Antiulcerative drugs were frequently prescribed in the elderly inpatients. The adverse drug reaction could possibly be due to drug interaction. The study results could be used as fundamental data for further drug utilization review of antiulcerative agents.