['Although maternal smoking has been associated with child emotional and behavioral problems, to our knowledge, no study has evaluated the association between overall household smoking and such problems.', 'To investigate whether children who live with smokers are more likely than children who do not live with smokers to have emotional or behavioral problems and to explore this association in households with nonsmoking mothers.', 'Nationally representative data from the 2000 to 2004 medical expenditure panel surveys, involving 30,668 children aged 5 to 17 years, were used. Associations between child emotional or behavioral problems and household smoking, and child, maternal, and family characteristics were examined. SUDAAN software was used to adjust for complex sampling design.', 'Overall score on the Columbia Impairment Scale, a 13-item parent-report measure of child emotional or behavioral functioning (range, 0-52, >or=16 indicates a child with such problems).', 'Children in smoking versus nonsmoking households were significantly more likely to have behavioral problems (17.39% vs 9.29%, p < .001). After adjusting for all covariates, male sex, older age of child, younger age of mother, unmarried mother, maternal depression, and below average maternal physical and mental health, each were independently associated with increased likelihood of emotional and behavioral problems, as was the presence of one or more adult smokers in the household (adjusted odds ratio 1.42; 95% confidence interval: 1.26-1.60). The odds of Columbia Impairment Scale score >or=16 increased with increasing number of smokers in the household, even among children whose mothers did not smoke.'] Is adult household smoking associated with increased child emotional and behavioral problems?