BACKGROUND: Tobacco smoke exposure increases breathing problems of children. Texas Children's Health Plan is a Managed Medicaid and Children's Health Insurance Program (CHIP) managed care provider. The aim of this study is to determine associations among tobacco smoke exposure, asthma prevalence, and asthma health-care utilization. METHODS: Texas Children's Health Plan conducts an annual survey of members who have a physician visit. Questions were added to the survey in March 2010 about asthma and tobacco smoke exposure. Survey results for children < 18 years of age were matched to health plan claims data for the 12 months following the date of the physician visit. RESULTS: A total of 22,470 parents of unique members/patients from birth to < 18 years of age participated in the survey. More whites than African Americans or Hispanics report that the child's mother is a smoker (19.5% vs 9.1% and vs 2.3%, respectively; P < .001). Compared with children whose mother does not smoke, parent report of asthma diagnosis and claims for dispensing of short-acting beta agonist medication are greater if the mother is a smoker (adjusted OR, 1.20 [95% CI, 1.03-1.40] and 1.24 [95% CI, 1.08-1.42], respectively). In contrast to Medicaid, in which there are no out-of-pocket costs, the CHIP line of business requires copays for ED visits. ED visits are influenced by maternal smoking only in the CHIP line of business (adjusted OR, 4.40; 95% CI, 1.69-11.44). CONCLUSION: Maternal smoking increases risk for asthma diagnosis and prescription of asthma quick relief medication. Maternal smoking predicted asthma-related ED visits only for the CHIP line of business.