Produced waters are characterized with respect to the amounts and chemical constituents generated in oil and gas production. Removal of portions of total suspended solids, total dissolved solids, volatile organic chemicals, and adsorbable organic chemicals were simulated and costs associated with each treatment scenario have been estimated. Treatment facility size is a key parameter in determining unit cost. Desalination was the most costly process evaluated. Produced water treatment costs range from 0.25to$35.00/m\sp3$ and are dependent on the nature and level of treatment. Under the most cost-effective scenario, the industry-wide cost of removing emulsified oils and dissolved organic materials to a level suitable for coastal discharge is approximately 4.00$/m\sp3$. This translates to an annual industry-wide cost of some twenty billion dollars. Costs for reclaiming produced water for agricultural purposes may be as high as 35.00/m sp3$ due to desalting costs.