Contaminants of emerging concern including pharmaceuticals and persistent organic pollutants are increasingly detected in estuaries and waterways. Although there are growing number of studies on the toxicity of contaminants of emerging concern, its impact on marine invertebrates and specifically on hemocytes is less well studied. The eastern oyster Crassostrea virginica is a filter feeder that is exposed to a variety of compounds in the seawater within its natural habitat. Hemocytes, the main immune effectors of C. virginica, are potentially exposed to the various bioaccumulated compounds. The purpose of this study is to identify the impact of a few of these contaminants of emerging concern such as the beta-blocker atenolol on oyster hemocyte function. Globally, atenolol has been found in wastewater at concentrations as high as approximately 1uM. In this study, hemolymph was collected from C. virginica and collected hemocytes were exposed in-vitro to environmentally relevant concentrations of atenolol over a 24-hour period. Flow cytometry and function assays including viability, phagocytosis, reactive oxygen species, lysosomes and apoptosis were utilized to measure the impact of atenolol on hemocytes. Results suggest that in-vitro exposure of hemocytes to atenolol (0.04 nm to 1uM) did not significantly impact oyster hemocyte function. This study utilized C. virginica hemocytes to assess the impact of atenolol on hemocyte function and can be utilized as an in-vitro model for understanding the impacts of contaminants of emerging concern on bivalves. Further investigation on other types of contaminants of emerging concern are needed.