With congressional passage of the BEACH Act in October of 2000, Coastal and Great Lakes states were mandated to assess coastal recreation waters for the application of ambient water quality standards. This research encompasses two components involved in applying the BEACH Act statues to Oregon. The first component was to select beach sites in Oregon. The second component involves applying bacterial recreational water standards to select Oregon beaches. Using the guidelines provided by the United States Environmental Protection Agency (EPA), this study develops a method to appraise Oregon marine recreational waters taking into account the following factors: use, available information, pollution threats, sanitary surveys, monitoring data, exposure considerations, economics, and development. In an effort to protect the public from swimming-associated illness attributable to microbial pollution, 24 beaches were identified in Oregon. Of these, 19 beaches were classified as tier 1, or high priority, and five sites were classified as medium priority, or tier 2. Future studies should be directed at ascertaining the beach lengths utilized by Oregon marine recreators since this is an important parameter in targeting bacterial monitoring. Ongoing monitoring of these 24 sites is warranted and new information could be used to update beach tier levels in Oregon. In the second phase of this study, bacterial monitoring data was used for comparison to recreational water quality standards. In October of 2002, the Oregon Department of Environmental Quality (ODEQ) sampled 26 beaches for enterococci and Escherichia coli (E. coli) densities. Of the water sampled from all 26 beach sites, nine exceeded s single sample maximum density of 104 enterococci colony forming units (cfu) per 100 milliLiters (mL). The Oregon beach with the highest exceedance occurred at Otter Rock's South Cove where the enterococci concentration was 4352 most probable number (MPN)/100 mL. A comparison of the 26 sampled beaches to ODEQ's estuarine E. coli standard of 406 organisms/100 mL resulted in two beaches with exceedances. Otter Rock at South Cove had the highest E. coli concentration at 1850 MPN/100 mL. Based on the limited data used in this study, should Oregon adopt the enterococci standard in lieu of the current ODEQ estuarine E. coli standard, more beaches will have exceedances of the recreational water standard. Additional bacterial monitoring is warranted to further characterize the nature and extent of the problem in Oregon. To protect the health of the marine recreating public, future Oregon marine water quality studies should delineate the "no swim" zone around creeks and model the impacts of rainfall on beach sites. / Graduation date: 2004