Exposure to secondhand smoke causes adverse health outcomes particularly in vulnerable groups like children. This multi-centered prospective study examined the household exposure to secondhand smoke among asthmatic children presenting to emergency departments on O'ahu, Hawai'i. Findings revealed that asthmatic children of Samoan, Micronesian, Filipino, Part/Native Hawaiian and Other/Mixed Ancestry had a greater proportion of high exposure to secondhand smoke in the home compared to Japanese, Chinese and Caucasian ethnic groups. Asthmatic children with no insurance or with Medicaid had a greater frequency of high exposure to secondhand smoke in the home than those with private insurance. Additionally, an inverse relationship between caregiver educational level and exposure to secondhand smoke in the home was observed. Recommendations are provided to improve health outcomes and address the disproportionate burden of asthma in such children.