Background: Asthma is a heterogeneous disease characterized by cough, wheeze and shortness of breath that vary in intensity and time with variable expiratory airflow limitation, associated with chronic airway inflammation. Aim of the study was to assess the usefulness of Peak Expiratory Flow Rate [PEFR] and oxygen saturation in determining severity of acute asthma, to measure objective change in PEFR and oxygen saturation following bronchodilator therapy and the role of chest X-rays in acute asthma.Methods: A prospective study of 50 children above 5 years with acute asthma who presented to the emergency department in a tertiary care hospital were included. PEFR and oxygen saturation before and after bronchodilator therapy was measured. Indication for chest X-rays, its clinical correlation and change in standard treatment of acute asthma based on X-ray reports was noted.Results: The mean PEFR and PEFR % of expected was lower in severe asthma when compared to moderate asthma and was statistically significant (p<0.001). The % of expected PEFR before salbutamol therapy was 48.78±14.36, which improved significantly to 67.13±14.22 after treatment (p<0.001). Oxygen saturation before and after salbutamol therapy was 94.96 ± 4.11 and 96.96±2.87 respectively with the change being significant (p value <0.001). Chest X-rays were performed in 12 (24%) children as per standard guidelines, of which 1(9%) was abnormal showing right basal consolidation. Chest X-ray correlated with clinical findings in 1 child and the findings on chest X-ray altered the ongoing treatment by addition of antibiotic.Conclusions: PEFR and oxygen saturation is useful in the emergency department to objectively assess the severity of acute asthma and the response to initial bronchodilator therapy. Chest X-rays are not routinely indicated in the standard treatment of acute asthma.