Ethnic minorities of low socioeconomic status are disproportionately represented in the trends of increasing asthma prevalence, morbidity, and mortality. We surveyed a cohort of 998 fourth-grade students in an impoverished area of southeast San Diego with a high percentage of Hispanic Mexican-Americans. Of the 654 Hispanic 9-12-year-olds, 14.4% were categorized as probable current asthma (within the past year), based on symptom of wheezing or physician diagnosis of asthma [with respiratory symptom(s) or medication]. An additional 13.5% had respiratory symptoms indicating possible asthma. Differences by ethnic group in the percentage of probable asthma or related symptoms were highly significant (p < 0.0001). Among Hispanics with a category of probable asthma, only 57.4% had a physician diagnosis versus 80.6% of black and 85.7% of white students. The frequency of health insurance coverage differed significantly between ethnic groups (p < 0.0001), with Hispanics among the lowest (37.2%).