Lack of good management is the principal reason that most irrigation projects have failed to reach their potential. Thus concludes this review of A.I.D. irrigation projects, based on impact evaluations, other studies, and a 5/83 AID-sponsored conference on irrigation management. Included are discussions of types of irrigation systems; social and economic impacts; policies and investment strategies; management; maintenance and rehabilitation; and project planning, monitoring, and sustainability. Although irrigation normally improves yields, it is not a simple solution to food deficits. Socioeconomic impacts (on, e.g., civic participation, women, the environment) are difficult to assess. Irrigation systems range along a continuum from local management to external control. The former is most effective, yet traditional community-based systems are often ignored in policy considerations. Problems of water management, either by water user associations or implementing agency, are exacerbated by donors' bureaucratic priorities; involving farmers in planning undoubtedly leads to improved management. System maintenance is also best done at the local level. Existing water user associations should be encouraged and equitable cost recovery from users fostered. Irrigation project planning is subject to a series of pressures prompting hurried approval. Design problems include poor donor coordination and failure to adequately consider such factors as farmer needs, host country commitment, agronomic realities, and social context. Planning should be done within the context of natural resource strategy, and relationships between irrigated and nonirrigated areas understood. Issues such as system size, public vs. private, or rehabilitation vs. new construction are closely interrelated. Technology choice should allow maximum flexibility in design, installation, and operation. Agricultural triage (choosing between competing needs and goals) is usually dictated by fiscal constraints, but may reinforce income and social differences; a donor influencing policy should realize the implications thereof. Appended are a 9-page bibliography (1950-83), a list of A.I.D. irrigation studies, summaries and a discussion of the impact evaluations, and the conference proceedings.