**Abstract**

The CGIAR Challenge Program on Water and Food (CPWF) was conducted in the Karkheh River Basin (KRB) as one of the nine benchmark basins and a representative basin in the arid and semi-arid regions of the world in its phase one of implementation. The CPWF Program in the KRB began in 2003 and ended in 2008. Four focal projects, namely: 1) Water Productivity Improvement (WP), 2) Improvement of Livelihood Resilience of Local Communities in the Upper Catchments (LR), 3) Karkheh Basin Focal Project (BFP), and 4) a small grant project for Stakeholder Participation (SG) were implemented in the KRB. The international focal institutes in charge of these projects were ICARDA, IWMI, and the CENESTA Center (an NGO), respectively. These institutes implemented the mentioned projects in collaboration with the Iran country's national institutes/centers (NARES). In this chapter, the approaches of CPWF in implementing the program in KRB are explained and discussed. Moreover, some major achievements and lessons learned from implementing the mentioned focal projects are provided. Based on the results, it can be stated that the roadmap for improving water productivity from the plant to the basin scales, by considering the policy and institutional issues, has been drawn in the CPWF program in KRB. Moreover, for better management of upstream watersheds in KRB, integrated watershed management principles have been well formulated and developed, taking into account the livelihood resilience improvement issues of local communities. In general, it can be stated that the development of multidisciplinary research of national research institutes and collaboration with related international institutes is necessary to improve water productivity and integrated management of catchments and to solve water crisis in the KRB and Iran as a whole. The lessons learned from implementing the CPWF program in KRB could be used as a suitable model to improve the quality of future similar studies in Iran and Central Asia.

**Keywords:** CPWF, Karkheh River basin, stakeholder, water, agriculture
