Produced water is the primary waste stream generated during fossil fuel production, with the volumetric water-to-oil ratio approaching 50: 1 in the later stages of oil field production. In the United States, produced water is usually reinjected, either in support of enhanced oil recovery or for disposal. In and regions, reusing or recycling the treated water for irrigation or other purposes may be an economically and environmentally attractive alternative. Successful treatment of complex produced waters generally requires that a series of operations be used to remove different contaminants. Electrodialysis is one possible desalting technique. Recent results indicate that this approach may be appropriate for reclamation of produced waters with relatively low total dissolved solids (TDS) loads but is unlikely to be cost-effective for treatment of concentrated produced waters.