Water is the most crucial component in farming and knowledge of crop water requirements is essential for its efficient utilization in agriculture. Crop water requirements (CWR) are greatly influenced by climatic factors such as evapotranspiration, uneven rainfall distribution, soil fertility, and soil characteristics. Although Kohima district of Nagaland receives high rainfall the lack of adequate rainwater management conditions and inadequate soil and water conservation measures lead to severe water scarcity, especially in the post-monsoon period. Therefore, efficient water management requires efficient crop production for agricultural development and for improving the rural economy of Nagaland. The objective of this study was to use the FAO CROPWAT 8.0 model to determine the crop water need (CWR), irrigation water requirement (IWR), and irrigation schedule for some of the major crops grown in the Kohima district of Nagaland. Penman-Monteith method (FAO, 1998) is used in the present study for determining reference crop evapotranspiration (ET0) since it is reported to provide values that are very consistent with actual crop water use data worldwide. Crop, soil and climate data were collected from various sources and results were analysed. The analysis revealed that the average CWR for the rice, maize, soybean and potato was found to be 537.1,305.6, 292.2, and 364.2, mm/dec respectively and the average Irrigation requirement for rice, maize, soybean and potato crop was found to be 251.6, 54.9, 73 and 21.8 mm/dec respectively. It was observed that due to greater temperatures and low humidity, crop water requirements and irrigation water requirements were higher during the dry season. The findings of the study would be useful for water management and crop planning for the sustainability of agriculture in Nagaland.