In this study, we applied the prevalence and human capital approaches to estimate the total social cost of drug abuse in Taiwan in 1996 through the analysis of the cost of medical treatments, incarceration and the productivity loss caused by drug abuse. The preliminary results are as follows:(1)The total cost of incarceration was ca.2.06 billion NT dollars, and the average daily cost per person was ca. 248 NT dollars. (2)The total cost of drug-related medical treatments was ca. 2.38 billion NT dollars,and the average daily cost per person was 6,831 NT dollars. (3)The productivity loss due to drug abuse was ca. 6.05billion NT dollars. (4)The total aforementioned social cost was ca. 10.49 billion NT dollars. However, the total cost is likely to be underestimated because our data were mainly based on the abuse of methamphetamine, morphine and heroin. Other addiction-induced diseases, productivity loss and law offences were not included in this study yet. We anticipate a more detailed estimation of social cos t on drug abuse to be obtained through a rational adjustment of research design in the second-year study.