A study was undertaken to evaluate the performance of twelve 3-way cross broiler rabbit genetic groups with respect to their post weaning body weights from 6 to 16 weeks of age and to estimate the heterosis. The body weights at 6, 10 and 16 weeks of age were significantly influenced by the month of birth, whereas litter size at birth had significant influence on body weights at 6 and R weeks of age only. Genetic group had significant influence on the body weights at all the age groups studied. The overall least squares mean body weight at 6, 8, 10, 12, 14 and 16 weeks of age was 571.51±8.42, 874.62±11.24, 1012.55±13.09, 1244.73±15.06, 1437.80±16.07 and 1608.51±16.55 g, respectively. The 3-way cross bunnies terminally sired by Flemish Giant bucks recorded the highest body weight, which revealed the importance of the utilization of heavier breed like Flemish Giant as male line in the production of synthetic fryer rabbits. All the 12 genetic groups, except the SNF recorded the positive heterosis ranging from 0.51 to 41.95 per cent.