Hydroxylated Polychlorinated Biphenyls (OH-PCBs) are metabolites of Polychlorinated Biphenyls (PCBs), a class of ubiquitous environmental contaminants banned in the United States in the 1970s for their persistence in the environment and living organisms, and subsequent health effects. OH-PCBs are probable carcinogens, thyroid inhibitors, and can cause interference with neurological and behavioral development. People living in Brownsville, Texas in the Lower Rio Grande Valley are frequently exposed to substandard environmental quality, including pollution from Mexico, and are therefore vulnerable to a variety of health outcomes. A previous study of a group of mothers and infants living in Brownsville found low levels of PCBs in bloods. The present study investigated levels of OH-PCBs to further assess the significance of PCBs as contaminants of interest in the area. Though OH-PCBs levels were lower than expected, they were present in all blood samples, demonstrating transplacental transfer from mothers to infants. The results indicate that PCB exposure may no longer be of severe concern in this area. Further research into similar chemicals and additional health threats in the Lower Rio Grande Valley remains a high priority.