Bronchial asthma is a complex disorder involving many factors including the autonomic nervous system. It has now been possible to evaluate autonomic nervous system activity by analysis of beat-to-beat variability of heart rate. Our study was conducted on 15 children in acute attack of asthma, 15 stable asthmatic children, and another 20 children as control. The time domains in indices (SDNN RMS s.d., PNN50) were significantly reduced in acute asthmatics however in asymptomatic patients though they were reduced, the reduction was not of statistical significance. Frequency domain showed the following results: LF showed non-significant increase in acute asthmatics and asymptomatic asthmatics. There was statistical reduction in HF, increase in LF/HF ratio in acute asthmatics. The asymptomatic showed the same changes however, changes were not up to statistical significance. We conclude that all patients with bronchial asthma whether symptomatic or asymptomatic will show evidence of autonomic dysfunction.