The oil palm plantations are regenerated every 25 years and a large amount of scrapped wood from field is totally discarded without any use. In these experiments the possibility of utilizing oil palm trunks (OPT) as ruminant feed was considered. The lignin content of OPT was found to be low while the content of soluble sugars was high. Furthermore, the digestibility was markedly improved with NaOH treatment or steaming. The portion of parenchyma tissues separated from OPT showed a high digestibility even under untreated conditions. The performance of the steers fed on NaOH-treated or ensiled OPT ration for 8 months suggested that OPT could become a promising roughage source for ruminants.