There is a considerable overlap in the clinical presentation of acute asthma and ARI. According to the current ARI Control Programme recommendations, a child with cough and rapid breathing is overtreated for ARI (pneumonia) with antibiotics and undertreated for asthma with bronchodilators. The present study, therefore, evaluated simple predictors to differentiate these two conditions to refine the recommended case management. In a case control comparison, children between 6 to 60 months age who presented with cough and rapid breathing due to acute asthma (n = 100) and ARI (n = 100) were evaluated. Only 34% of asthmatics had an audible wheeze. Significant independent predictors on multiple logistic regression analysis were number of earlier similar attacks and fever (or temperature). The best predictor for asthma was two or more earlier similar episodes (sensitivity 84%, specificity 84%) followed by temperature < 37.6 degrees C (sensitivity 73% and specificity 84%). Absence of fever, audible wheeze and a family history of asthma had excellent specificities (98-100%) but low sensitivities (20-34%). It is concluded that simple clinical predictors can differentiate acute asthma and ARI. The recommended case management can, therefore, be refined by either: (i) Prescribing bronchodilators and no antibiotics with two or more earlier similar episodes of cough and rapid breathing; or (ii) To further minimize undertreatment for pneumonia, prescribing bronchodilators as above, but denying antibiotics in such cases only if there is audible wheeze or family history of asthma or no fever.