Objective. This study was designed to assess demographic and socioeconomic differences in blood lead levels (BLLs) among Mexican-American children and adolescents in the United States. Methods. We analyzed data from the Third National Health and Nutrition Examination Survey, 1988–1994, for 3,325 Mexican-American youth aged 1 to 17 years. The main study outcome measures included a continuous measure (μg/dL) of BLL and two dichotomous measures of BLL (⩾5 μg/dL and ⩾10 μg/dL). Results. The mean BLL among Mexican-American children in the United States was 3.45 μg/dL (95% confidence interval [CI] 3.07, 3.87); 20% had BLL ⩾5 μg/dL (95% CI 15%, 24%); and 4% had BLL ⩾10 μg/dL (95% CI 2%, 6%). In multivariate analyses, gender, age, generational status, home language, family income, education of head of household, age of housing, and source of drinking water were statistically significant independent predictors ( p<0.05) of having higher BLLs and of having BLL ⩾5 μg/dL, whereas age, family income, housing age, and source of drinking water were significant predictors ( p<0.05) of having BLL ⩾10 μg/dL. Conclusions. Significant differences in the risk of having elevated BLLs exist among Mexican-American youth. Those at greatest risk should be prioritized for lead screening and lead exposure abatement interventions.