Water requirements of oil palm close to crop evapotranspiration (ETc). The objectives of this research were to known the value of crop coefficient for the age of oil palm 4, 5 and 6 month and predicted water requirements of oil palm based on net radiation evaporation method. The result showed the value of oil palm for 4, 5, and 6 months were 0.50, 0.52, and 0.54. The value of reference evaporation (net radiation, ETo) range 2.89-4.25 mm. day− 1. Moreover, from predicted crop evapotranspiration showed that water requirements of oil palm range 1.44-3.70 mm. day− 1. Water requirements increasing based on the age of oil palm, however, it will decrease in the rainy season.