Napier grass (Pennisetum purpureum) has potential to be processed as a livestock fodder due to high growth rate and good nutritive value. The objective of this study is to determine and compare the chemical composition of Taiwan Napier grass at different growth stages. The different harvesting intervals of growth stages were 30 to 35 days and 40 to 45 days. The plant samples were collected at Agropolitan Farm Besut-Setiu, Terengganu and were analyzed using proximate analysis and dry ashing method. The chemical compositions were analyzed for ash, crude protein (CP), crude fiber (CF), ether extract (EE), Magnesium (Mg) and Potassium (K). The mineral compositions of Mg and K were measured using Induced Couple Plasma Optical Emission Spectrometry (ICP-OES). Results showed that the chemical compositions of Taiwan Napier grass at different growth stages had a significant effect on the percentage content of all components measured. The percentage of crude fiber increased as the age increased which is 28.88% and 30.04% in 30-35 days and 40-45 days, respectively. The percentage of chemical compositions of crude protein, ash, ether extract, Mg and K had decreased as the growth stage of Taiwan Napier grass increased. The percentage of crude protein, ash, ether extract, Mg and K were higher at 30-35 days, which are 14.42%, 10.57%, 3.00%, 0.064 ppm and 0.026 ppm, respectively. Therefore, it can be concluded that the growth stage at 30-35 days of Taiwan Napier grass is the best age for harvesting which is providing high nutritive value of the animal feed