As the population in Malaysia rise year by year, the demand for quality food also increasing especially animal protein. Nowadays, rabbit farming is gaining popularity in smallholder farmers as an alternative source of animal protein. However, a feed is one of the major constraints to make a profitable rabbit farming. Therefore, most of the farmer in Malaysia feed their livestock with forage like Napier grass to reduce the feed cost. But, the excessive intake Napier grass containing oxalic acid can cause health problems to a rabbit. This study was conducted to observe the effect of substituting the pellet with Napier grass (Pennisetumpurpureum) that contain oxalic acid on feed intake, growth performance and carcass composition of rabbits (Oryctolaguscuniculus). Nine early weaned rabbit was treated with three different treatments. Treatment 1 was given 50% concentrate and Napier grass ad libitum. Treatment 2 was given 75% concentrate and Napier grass ad libitum. Treatment 3 was given with 100% concentrate. To measure the feed intake of the rabbits, the amount of dry matter of feed consumed by the rabbit was weighed daily. The body weight of the subject was weighed weekly to measure the growth performance. The weight of feet, head, spleen, lungs, heart, kidneys, liver, stomach, intestine and tail were weighed to make a comparison of carcass composition of these three treatments. The results showed that total dry matter intake by treatment 2 were the highest. The growth rate of treatment 3 was the highest which is 77.169%, followed by treatment 2 which is 74.278% and treatment 1 which is 46.023%. In conclusion, the best way to increase the amount of dry matter intake by the rabbit while reducing the amount of concentrate is by providing supplementary feed like Napier grass on the rabbit diet although it only giving moderate growth performance.