Latino and African American children with asthma are at increased risk for asthma morbidity compared with non-Latino White children. Environmental control (ie, environmental exposures and family strategies to control them) may contribute to greater asthma morbidity for ethnic minority children living in urban environments. This study examined ethnic differences in a semi-structured assessment of environmental control, associations between environmental control and asthma outcomes (asthma control, functional limitation, and emergency department [ED] use), and ethnic differences in environmental triggers in a sample of urban Latino, African American, and non-Latino White families. One hundred thirty-three children (6-13 years of age) and their caregivers completed demographic questionnaires, measures of asthma control and morbidity, and a semi-structured interview assessing environmental control. Reported environmental control differed significantly by ethnicity (P<0.05), with Latino families reporting higher levels of environmental control. Reported environmental control was significantly associated with asthma control (P<0.017) and functional limitation (P<0.017). Reported environmental control and ED use were significantly associated in Latino families (P<0.05). Non-Latino White and African American families reported more secondhand smoke exposure than Latino families (P<0.001). Latino families reported more optimal home environmental control than other ethnic groups. Substantial ethnic differences in asthma triggers suggest that observed ethnic disparities in asthma may be due, at least in part, to differences in the home environment.