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As part of our ongoing work with the EPA-sponsored Great Lakes Fish Monitoring and Surveillance Program, we have been analyzing Great Lakes fish tissue samples since 2004 for a suite of legacy and emerging contaminants of concern. Whole fish Lake Trout composites from all five Great Lakes have been extracted and analyzed using GC/ECD, GC/MS, GC/MS/MS, and GCxGC/TOF-MS to identify and quantify analytes such as PCBs, dioxins, organochlorine pesticides, flame retardants, and PFOS. In this work we will report on concentrations and temporal trends of toxaphene in top predatory Great Lakes fish over the past seventeen years. Toxaphene is a complex mixture of hundreds of chlorinated bornanes and camphenes that was used as a pesticide in the 1960s and 1970s, primarily on cotton crops in the southern United States. It is believed that atmospheric transport processes have led to deposition of toxaphene into the Great Lakes, and their subsequent bioaccumulation in the food web. Since 2004, we have measured toxaphene concentrations in Great Lakes fish to decrease by approximately a factor of three. Lake Trout samples collected in 2019 show the following concentrations, in order from highest to lowest: L. Superior = 115 ng/g, L. Michigan = 81 ng/g, L. Huron = 55 ng/g, L. Ontario = 47 ng/g, and L. Erie = 39 ng/g. [ABSTRACT FROM AUTHOR]