This paper examines the characteristics of a traditional farmer-managed irrigation system in Nigeria, through the presentation of a detailed case study. It documents the development of a traditional irrigation system in the inland valley of the Bida region in central Nigeria and the features of its operation and management. The physical structure and the composition of system users were surveyed in detail. In addition, the characteristics of community management of several irrigation systems in the region were investigated. Farmers were able to mobilize necessary local resources for irrigation development and maintenance although they did this without any external support. The irrigation management institution in the area was highly linked to the local land tenure system. The involvement of landlords in the irrigation community greatly affected the performance of irrigation management. There was no clear definition of water rights. In times of water shortage, water was rotated and shared but water scrambling had become a severe problem in recent years with the higher demand for off-season crops. Irrigation communities were organized informally without tiers of nested organizations. Unfairness in water distribution and contribution to system maintenance existed between top-enders and tail-enders of irrigation canals. Nevertheless, the multi-layered and fragmented land ownership of the region made coordination among different irrigation communities difficult and the unfairness problem could not be solved without institutional changes.