The purpose of this study determined whether use of student random drug testing provided an effective means to reduce drug usage by secondary school students. The participants included 50,214 7th through 12th grade students in 12 selected public schools. All school districts participated in the Texas School Survey of Substance Use in 1994, 1996, 1998, and 2000. The six districts in the experimental group used drug testing as a method of reducing drug usage among students. The six districts in the control group did not use drug testing. Although athletes and students involved in extracurricular activities remain the focus of random dug testing, this research focused on an entire school population to determine whether drug testing only a select group of students reduced reported drug usage in the entire school. Two questions guided the research: First, does the use of random drug testing have an impact on student drug usage? Second, does the year of implementation of random drug testing have an impact on students' self-reported drug usage? The findings for each research question were categorized according to nine illegal drugs. The researcher used a one-way repeated measures factorial design. The data were analyzed via the univariate (split-plot) 2 x …