A study was undertaken to examine the effect of a high-energy electron beam on waterborne microorganisms. Electron beam technology has been used for a wide variety of applications, including biological, medical, chemical and physical. As a water treatment technology, electron beams are environmentally friendly, produce no toxic wastes or residual radiation, and are very energy efficient. The electron beam study was conducted on a large scale at the Virginia Key Wastewater Treatment Plant, Miami, Florida. Preliminary studies suggested that a wastewater population of coliphage and total coliforms were reduced by 3 log[10] at an electron beam dose of 500 krads. This study showed a similar inactivation. Hydrodynamic tests showed that 4-6 um latex spheres were homogeneously distributed in 4,000 gallons of dechlorinated tap water. At 400 krads, 4.01 and 4.74 log[10] inactivations for Klebsiella terrigena and PRD1 Salmonella phage were observed, respectively. The preliminary findings of this study suggest that electron beam technology can be used to treat water to reduce the number of viable microorganisms, and may have application for routine water treatment. Includes 13 references, table, figures.