Per- and polyfluoroaklyl substances (PFAS) of are of interest due to their persistence and ubiquity in the environment and their potential health and environmental effects. While these compounds have been well studied in the past 10 years, little is known about PFAS in oil and gas produced waters, which are voluminous and have the potential to impact the environment through surficial spills and groundwater contamination. This study aims to provide the first known analyses of PFAS in oil and gas produced waters. Samples including hydraulic fracturing fluid, water from two input ponds used to mix fracture fluid, and produced water from three wells in the Niobrara formation in the Denver Basin were collected and analyzed for PFAS. Time series samples from the three wells were collected from day 1 of production through approximately one year. For the day 1 production samples from the time series wells, both targeted PFAS using EPA Draft 1633 method and total oxidizable precursors (TOP) analyses were performed.