OBJECTIVE: Recognition of the complexity of asthma management has led to the development of asthma treatment guidelines that include the recommendation that all pediatric asthma patients receive a written asthma action plan. We assessed the readability, suitability, and characteristics of asthma action plans, elements that contribute to the effectiveness of action plan use, particularly for those with limited literacy. METHODS: This was a descriptive study of 30 asthma action plans (27 state Department of Health (DOH)-endorsed, 3 national action plans endorsed by 6 states). Outcome measures: (1) readability (as assessed by Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, Simple Measure of Gobbledygook, Forcast), (2) suitability (Suitability Assessment of Materials [SAM], adequate: >/= 0.4; unsuitable: <0.4), (3) action plan characteristics (peak flow vs symptom-based, symptoms, recommended actions). RESULTS: Mean (SD) overall readability grade level was 7.2 (1.1) (range = 5.7-9.8); 70.0% were above a sixth-grade level. Mean (SD) suitability score was 0.74 (0.14). Overall, all action plans were found to be adequate, although 40.0% had an unsuitable score in at least 1 factor. The highest percent of unsuitable scores were found in the categories of layout/typography (30.0%), learning stimulation/motivation (26.7%), and graphics (13.3%). There were no statistically significant differences between the average grade level or SAM score of state DOH developed action plans and those from or adapted from national organizations. Plans varied with respect to terms used, symptoms included, and recommended actions. CONCLUSIONS: Specific improvements in asthma action plans could maximize patient and parent understanding of appropriate asthma management and could particularly benefit individuals with limited literacy skills.