Purpose: The purpose was to identify the risk of drug use by adolescents. Method: The participants were 933 male students in the first grade of a high school in D city. The data were collected from Aug. 5th to Oct. 30th, 2004. The instrument was the High Risk Group Adolescent Drug User Screening Test(HIRIGADUST) developed by the Korea Adolescent Society(1996). The data were analyzed using SPSS. Results: For substance use, 64.5% of the students answered that they had drunk, 40.3% that they had smoked, and 2.0% that they had tried drug use. For scores on HIRIGADUST regarding socio-demographic characteristics, there were significant differences depending on school type, personality, academic performance, economic status, and ability to talk with parents. For scores on HIRIGADUST regarding drug using-related characteristics, there were significant differences depending on drinking experience, frequency of drinking, amount of alcohol intake, smoking experience and number of cigarettes smoked. Of the students 27.2% students were in the high risk group. Conclusion: In schools, systematic and intensive assessment of drug use should be done, and if needed, a service system connected to clinics specializing in drug addiction should be established. Prevention education should be carried out continuously.