Abstract: BACKGROUND:It is known that small for gestational age (SGA) babies may be at an increased risk of cardiovascular diseases during adulthood. There is paucity of literature regarding comparative cardiac functions of SGA and appropriate for gestational age (AGA) babies in neonatal period. The present study was conceived to compare the cardiac function of term small and appropriate for gestational age (AGA) babies through a relatively novel echocardiographic index in early neonatal period. OBJECTIVES:To compare values of myocardial performance index (MPI) index (MPI = IVCT + IVRT/ET) at 48–72 hours of age among AGA and SGA babies. METHODS:Morphological and anthropometric assessment of serially born term babies was done at time of birth to recruit hundred each of AGA and SGA babies. Tissue Doppler Imaging (TDI) was done between 48–72 hours for each enrolled baby to assess both right and left ventricle MPI in each group. RESULTS:Mean±SD values for right ventricular MPI in AGA and SGA groups were 0.268 + 0.007 and 0.30 + 0.026 respectively (p < 0.001). Mean±SD values for left ventricular MPI in AGA and SGA groups were 0.25 + 0.012 and 0.30 + 0.017 respectively (p < 0.001). There was significant negative correlation between MPI values for either ventricles and the birth weight (spearmen’s rho of –0.66) (p < 0.001). Mean±SD values for LVET in AGA and SGA group were 0.304 + 0.026 and 0.266 + 0.032 respectively (p < 0.001). CONCLUSION:MPI had a higher absolute value in the SGA babies as compared to AGA babies. These observations point towards suboptimal cardiac performance among SGA babies as compared to AGA babies on the basis of myocardial performance index.