This project was a short-term field experiment conducted in summer 2010 and designed to provide preliminary data on the bioextraction (removal) of carbon (C) and nitrogen (N) for two different size classes (both <76mm shell height) of eastern oysters (Crassostrea virginica) at six sites in the Great Bay estuarine system in New Hampshire. Sites were chosen to represent a range of ambient nutrient concentrations, water flow conditions, and location within the estuary. Two of the sites were at oyster aquaculture farms: Granite State Shellfish at the mouth of the Oyster River, and Little Bay Oyster Company near Fox Point in Little Bay. At each site, oysters were deployed in 10mm mesh polyethylene bags typically used on oyster farms in New England. Approximately one thousand seed size (10-15 mm shell height), or two hundred (200) 1-year old (30-40 mm shell height) oysters were placed into each bag. Two bags (one for each size class) were suspended 10-20 cm off the bottom attached to plastic coated wire cages at each site from August 9 until November 4, 2010. The oysters were inspected and the bags were cleaned each month to reduce fouling. There were no significant differences in final size among the six sites, indicating similar growth rates. Soft tissue percetn C and percent N values, however, varied substantially and significantly (ANOVA, P<0.05) among the sites. Tukey tests indicated significantly higher percent C and percent N at the Squamscott River (SQ) site, and significantly lower at the Little Bay Oyster (LBO) farm site, compared to the other sites. The ranges of mean soft tissue percent C and %N were, respectively, 26.9 to 47.2 and 4.7 to 10.6.