Seasonal water deficit and climate change are among the major problems affecting the production and productivity of coffee arabica (coffee arabica L.). For its cultivation, farmers use irrigation but, they never realize how much water to apply. Therefore, the objective of this study was to determine the crop water requirement, irrigation water requirement and schedule for the cultivation of coffee Arabica in Somodo watershed. It was determined by using CROPWAT8.0 by dividing the development stage of the crop in to four season; initial, development, mid and late season and carried out with inputs of climatic, crop and soil data. Soil samples were collected at five different depths to determine irrigation schedule. The result reveals that CWR of the crop was 217mm, 430mm, 497mm and 424mm; and IWR was 205mm, 334mm, 67mm and 87mm depth of water per tree for the initial, development, mid and late season, respectively. Irrigation schedule starts on January first, 25th day, 45th day, 68 th day, 101 st day, and 305 th day with a gross quantity of 173.7mm, 136.8mm, 140.5mm, 148.8mm, and 159.4mm depth of water per tree, respectively. However, Investigation should continue from seedling stage to relate the yield and growth parameter of the crop.