OBJECTIVE The study was undertaken with the aim to determine correlation between the initial plasma cortisol level and severity of asthma attack and the response to standard treatment for acute exacerbation of bronchial asthma in pediatric age group. METHODS The study was performed in 33 asthmatic patients between 5-12 years of age, presenting to pediatric emergency with acute exacerbation of bronchial asthma. None of the patients included in the present study was on steroids. Venous blood sample for determination of plasma cortisol level was taken and patients were nebulized with salbutamol every 20 minutes, up to 1 hour. The patients who failed to respond even after three nebulizations were labeled as nonresponders and repeat venous blood sample for plasma cortisol estimation was taken before giving injection hydrocortisone. In responders sample was taken 1 hour after last nebulization. RESULTS The mean plasma cortisol value at the time of admission in responders (12.42 +/- 1.9 microg/dl) was not found to be significantly different from that in nonresponders (13.1 +/- 2.74 microg/dl). Children with severe attack of asthma had significantly higher plasma cortisol levels both at the time of admission (p=0.03) and at the end of study (p=0.001), as compared to patients with moderate attack. The mean percentage change in plasma cortisol levels in nonresponders was an increase of 80.65 +/- 60.64%, whereas, in responders it decreased by 16.49 +/- 21.7% and this difference was statistically significant (p<0.05). CONCLUSIONS The hypothalamo pituitary adrenal axis functions normally in asthmatic patients, producing a rise in cortisol levels corresponding to degree of stress; and from initial cortisol level alone, it cannot be predicted, whether a patient will respond to beta-2 agonist (salbutamol) nebulization alone or will require exogenous corticosteroids.