As the worldwide production of palm oil is increasing, concomitant wastes of unutilized parts of the oil palm is also increasing. Thus, effective utilization of these wastes is expected. In this paper, therefore, the chemical composition of cellulose, hemicellulose, lignin and other minor cell wall components was studied for six different parts of the oil palm such as trunk, frond, mesocarp, shell, kernel cake and empty fruit bunch (EFB). As a result, it was shown that cellulose is in a range between 20-40wt% with hemicellulose being 10-35wt%, whereas lignin in a range between 23-52wt%. More in detail, the shell contained the highest lignin about 52wt% but the kernel cake no lignin, while the rest in a range between 23-35wt%, being composed of guaiacyl and syringyl moieties without p-hydroxyphenyl residue. This is very similar to the hardwood-type lignin, rather than softwood-type lignin. On hemicellulose, mannan was rich in kernel cake, while glucuronoxylan rich in the other parts, with 1.8-8.5 xylose units per one uronic acid. These lines of information are useful for the efficient utilization of the whole parts of the oil palm which is necessary for the sustainable development of the biomass resources.