Problems of Adverse Drug Reaction (ADR) have been regarded as growing social concern in health. The purposes of this study were to analyze current domestic and foreign adverse drug reaction monitoring system and to develop a web-based reporting system and to test its performance. Two university hospitals, one clinic, and six pharmaceutical companies were participated in this pilot project. From March 1 to Oct. 30, 1998, a total of 310 cases were reported fromm the participating two hospitals. Of these, 240 cases were mild(77.42%), 61 cases were moderate(19.68%), and 9 cases were severe cases(2.9%). More ADR cases were report from the outpatients(83.22%) than inpatients. Oral intake was the most common route of administration(74.2%). A future ADR monitoring system was also presented in this paper.