The prevalence of overall or "generic" tobacco use among Hispanic, white, Black and Asian youths in grades four, seven, ten and twelve was compared in San Diego, California (n = 4980). Significant differences in generic tobacco use between ethnic groups were found in the 4th, 10th and 12th grades, but were greatest in the 10th grade. Only white youths demonstrated a sharp increase in regular tobacco use (once a month or more) between 7th and 10th grade. Overall, the prevalence of regular use was highest among whites (25.8%), followed by Hispanics (19.7%), Blacks (17.6%) and Asians (12.6%). Marijuana, alcohol, and other drug use explained approximately 40 percent of the variance in tobacco use in each ethnic group. Other predictors varied by ethnicity and included socioeconomic status, happiness of student, strictness of parent, adult tobacco use at home, accessibility to marijuana, and gender.