In this study the use of marijuana by high school students ranking from the lower to the upper socioeconomic class and including Blacks, Mexican-Americans, and Anglos was compared over a 3-year period. Analyses of the data revealed that the Preston and Hays findings of the incidence of reported marijuana use were comparable, and the different instruments and methodologies used by each investigator yielded data that were similar in pattern and frequency. The major finding was that marijuana use varies according to the ethnic and socioeconomic group examined.