Introduction: Body postural changes are commonly used in the management of patients with acute cardiopulmonary dysfunction. Size, shape and position of heart are related to the body type, posture and respiration. Effect of change in body posture on electrical axis of heart has not been well documented..The present study was conducted to study the effect of posture on electrical axis of heart during different phases of breathing in normal subjects. Aim: To study the effect of posture on electrical axis of heart during different phases of breathing. Materials and Method: With the help of INCO RMS Vesta 101 electrocardiograph, ECG was recorded in the following normal breathing, deep inspiration and deep expiration in supine, standing and sitting posture. Results: The mean cardiac axis after deep expiration in supine posture was +47.29 degrees, in the sitting posture it was +32.67 degrees and in standing posture it was +30.69 degrees. The decrease in cardiac axis upon assuming sitting posture was significantly different from the value obtained during supine posture (P<0.05). The decrease in cardiac axis upon assuming standing posture was significantly different from the value obtained during supine posture (P<0.01). Conclusion: It was found inter-individual variability in electrical axis of heart which can be explained on the basis of orientation of heart in the chest. In the present study, the decrease in cardiac axis due to postural variation from supine to sitting and standing was more pronounced after deep expiration. There was decrease in electrical axis of heart (shift to left) when subject changed the posture from supine to sitting and standing. © 2020 Elsevier B.V., All rights reserved.