ICID has been organizing its flagship triennial event International Congress on Irrigation and Drainage since 1951.  The 1st ICID Congress was held in 1951 at Delhi and so far ICID has held 23 Triennial Congresses, the most recent 23rd ICID Congress being held in Mexico City in October 2017. The list of questions addressed by the Congresses clearly indicates a progressive shift from purely technical questions to sustainability of irrigation and global water and food security issues. For example, questions for the second Congress (1954) were the problems of freeboard in irrigation canals, the maintenance of irrigation canals with special reference to weed control and safe yields and recharge of groundwater. At the 5th Congress (1963) the question of economics and financing of irrigation and flood control works and rehabilitation and modernization of irrigation and drainage systems appeared at the 11th Congress in Grenoble in 1981. The effect of irrigation and drainage was introduced at the 14th Congress in Rio (1990). Water management and institutional aspects were introduced at the 15th Congress in The Hague in 1993.  Sustainability of irrigation and farmer participation were the two questions of the 16thCongress in Cairo (1996) and at the 18th Congress in Montreal (2003) the questions of food production under water scarcity, poverty alleviation and environmental challenges. 

The ICID triennial Congresses focus on the upcoming issues that need to be addressed in irrigation, drainage and flood management. The Congresses also provide a platform for reviewing a number of contentious issues concerning the future of irrigation water vis-à-vis increased demands for competitive uses of water.

During the Congress, papers are presented and discussed for two Questions, a Special Session, Symposium, and History Seminar. Participation is usually open to all National Committees and their members, to the nationals of member countries, other qualified international organizations, and some of the invited non-member countries.  

The technical proceedings of the Congresses are compiled in the form of Transactions which are considered to be an authoritative guide and reference volume to researchers and professionals across the world, including farmers at grass root level.