The placenta is a vital organ for maintaining pregnancy and fetal development. We studied the influence of placental morphometric measurements (weight and diameter) on the body mass index (BMI) of the newborn. The present study was carried out at Dr. BR Ambedkar medical college and KC General Hospital Bangalore. Hundred and eight mothers who gave birth to uncomplicated singleton pregnancy, and their newborn were examined. Placental weight, diameter, birthweight and crown to heel length were recorded immediately after delivery by electronic weighing balance, Infantometer and measuring tape. BMI was calculated in kgs/m2. 58 Females and 50 Males new born babies were classified on the basis of body mass index (kg/m2) into 3 groups. Group I BMI <10, Group II BMI 10-13 and Group III BMI >13. The mean placental weight (in gms) and diameter (in cms) for the male babies in the Group II and III were 466.01 ± 78.23, 524.4 ± 39.51 and 16.9 ±0.69, 18.2 ± 1.05 respectively. However there were no babies in Group I. The mean placental weight (in gms) and diameter (in cms) for the female babies in the 3 groups were 409.6± 42.74, 489.7 ± 43.57, 521.4 ± 48.7 and 15.8 ± 1.01, 17.0± 0.81 and 17.2 ± 0.76 respectively. There was a statistically significant correlation between placental weight and diameter with BMI of the newborn in Group II and III for male babies and Group I and II for female babies (P<0.05).