This paper investigates the relation between collective action and performance for a case study in the Office du Niger irrigation scheme in Mali. As a result of irrigation management transfer at tertiary level, farmers are now collectively responsible for water supply to the tertiary block, water allocation within the tertiary block, coordination of the cropping calendar and infrastructure maintenance. The research is based on a field study including about 300 farmers from 36 tertiary blocks and 9 villages. First, the different aspects of both collective action and performance are measured through developing indicators. Regarding collective action, these indicators measure coordination of the cropping calendar, maintenance of tertiary infrastructure, coordination of water demand at tertiary level, and coordination of water allocation within the tertiary block. The performance indicators incorporate the viewpoint of the irrigation scheme's management as well as farmers and are irrigation efficiency, easiness of irrigation, occurrence of conflicts and agricultural productivity. Next, the relation between collective action and irrigation performance is quantified using statistical models. The main finding is that not all aspects of performance are affected by collective action, and when they do, not by all aspects of collective action. The choice of indicators when studying collective action is thus of primary importance. In the Office du Niger, coordination of water supply and demand and coordination of water allocation affect efficiency and easiness of irrigation respectively. Given the increasing importance of these aspects of performance, they must form the primary focus of efforts to enhance collective action.