beta 2 agonists are first election drugs for the treatment of asthma exacerbations. However, rates of complications derived from this asthma therapy like cardiovascular effects have addressed question marks on a possible paradoxical condition, leading to an increased mortality rate. The study was open label, non controlled and aimed to assess the effect of albuterol nebulizations on serum potassium levels, arterial oxygen saturation and electrocardiographic changes in asthma exacerbation in pediatric patients. Albuterol was administered at a dose of 150 mcg/kg/course for 10 minutes in two occasions. Thirty children with mild to moderate asthmatic exacerbation, admitted to emergency room, were included in the study. Bronchodilators administration in the previous 24 hours and history of cardiac or metabolic disease were considered exclusion criteria. Drugs affecting serum potassium were not allowed. Severity of exacerbation was rated by the Wood-Downes criteria. Average sample age was 7.4 +/- 1 years, heart rate increased from 111 +/- 23.23 to 130.0 +/- 22.14 beats/minute, with no clinical significance; serum potassium levels decreased from 4.47 +/- 0.52 to 3.73 +/- 0.49 mEq/L between baseline and final visits, respectively; QTc interval was significantly enlarged from 0.397 to 0.418 milliseconds between initial and final records (p < 0.001), but had no clinical meaning. No arrhythmias were recorded. Pulse oxymetry did not show significant changes (90.6 +/- 3.0% and 92.1 +/- 3.2 at baseline and final visits). The most common reported adverse event was distal tremor, which was present in 80% of the cases. Neither serum potassium decrement nor prolonged QTc after albuterol had clinical significance. Albuterol is a safe drug for the treatment of mild to moderate asthma exacerbations in pediatric patients.