Prescription of daily inhaled corticosteroids for children with persistent asthma is infrequent compared with national practice guidelines. The authors conducted a national, cross-sectional survey of pediatricians and family physicians to identify specialty differences and factors associated with physician nonadherence to National Heart, Lung, and Blood Institute guidelines for prescribing inhaled corticosteroids. Adherence was defined as following the recommendation for >90% of cases. Response rate was 49% (343/694). Pediatrician and family physicians reported similar rates of adherence (54% vs 51%). Pediatricians and family physicians reported different barriers. Although both groups indicated that parent hesitancy and nonadherence were common barriers, the most common barrier for family physicians was a perceived cost of the asthma medications for families. Pediatricians were more likely to indicate that lack of time (21% vs 10%) was a barrier to prescribing inhaled corticosteroids. In multivariate logistic analysis, the lack of a family/practice barrier (odds ratio, 0.27; 95% confidence interval, 0.13, 0.55) and physician agreement with the National Heart, Lung, and Blood Institute recommendation (odds ratio, 4.21; 95% confidence interval, 1.43, 12.3) was associated with self-reported adherence. Interventions to improve prescribing of inhaled corticosteroids should include strategies to address issues specific to pediatricians and family physicians.