The state of the art and potential application to Egypt of the conjunctive (or combined) use of surface and groundwater via an integrated reservoir system are reviewed in this report. Following introductory remarks on Egypt's water situation, the art and science of conjunctive water use are discussed in terms of its evolution, definition and use, advantages and disadvantages, methodologies, physical aspects, river flows, water quality, economics, institutional aspects, and maintenance and modeling. A discussion of specific aspects of conjunctive water use in Egypt covers factors and problems, surface water and groundwater supply and quality, drainage water and reuse, salinity due to waterlogging, water budget, and feasibility. Pertinent data and analyses from technical reports generated by the Egypt Water Use and Management Project are included. Conjunctive water use, it is concluded, is essential if Egypt is to solve its long-term water supply problems. Specific recommendations are made for field studies - still largely lacking - in the technical, economic, and sociopolitical aspects of the technology. A 55-item bibliography (1942-84) is appended. (Author abstract, modified).