BACKGROUND: According to National Institutes of Health (NIH) guidelines, asthma control and severity are unique constructs. Little is known about how asthma control and severity are distinguished by pediatricians and if they influence treatment recommendations. METHODS: We conducted a random-sample survey of 500 pediatricians using patient vignettes with different asthma status indicators (recent hospitalization, parental report of bother from asthma, frequent symptoms, parental report of worsening asthma, and wheeze during physical exam) and a visual analog scale (VAS) to rate control and severity. Regression models assessed the independent effects of these indicators on asthma control and severity ratings, and the effects of these ratings on treatment recommendations. RESULTS: A total of 270 respondents provided usable data. Compared to patients with well-controlled asthma: (1) medication intensity influenced only severity ratings; (2) frequent symptoms and recent hospitalization influenced control and severity ratings; (3) wheeze and bother influenced control ratings only (p<0.001 for all comparisons); (4) a report of worse asthma did not significantly affect any ratings (p>0.2). Poorer VAS control ratings were associated with recommendations to step-up treatment (odds ratio [OR] 2.61, 95% confidence interval [CI], 2.2-3.1, p<0.001), but more severe VAS ratings were not (OR 1.02, 95% CI, 0.9-1.2, p=0.8). Recommendations to step-down treatment were associated with poorer VAS control ratings (OR 0.70, 95% CI, 0.6-0.8, p<0.001) and more severe VAS ratings (OR 0.82, 95% CI, 0.7-0.9, p<0.001). CONCLUSIONS: Pediatricians who step-up asthma treatment base their assessments on asthma control, while assessments of both control and severity factor into their decision to step-down asthma therapy.