Aims: to know the influence of yoga on autonomic functions of the body. Material and Methods: The present prospective case control study was conducted among patients visited the OPD, ICARE Institute of Medical Science and Research &Dr.Bidhan Chandra Roy Hospital, Haldia,West Bengal, India. The findings were tabulated and subjected to statistical analysis. Case group (N=30): subjects who were performing regular yoga asanas and relaxation techniques for at least 5 years. Control group (N=30): age and gender matched subject who were not performing yoga asanas and relaxation techniques or were not engaged with any other type of physical exercises. Results: Amongst the sympathetic nervous system parameters, statistically significant difference existed between cases and controls for the Resting Heart Rate, Resting Diastolic Blood Pressure, Hand grip systolic blood pressure and Hand grip systolic blood pressure (p<0.05) respectively. Conclusion: yogic activity significantly alters the sympathetic activity like heart rate and blood pressure.