ABSTRACT Monitored natural recovery (MNR) is a response action for contaminated sediment that relies on natural processes to reduce ecological and human health risks to acceptable levels over time. Multi-media long-term monitoring is necessary to verify remedy effectiveness and success. Whereas MNR has most often been employed together with other engineered remedies to address contaminated sediment, this case study describes an evaluation demonstrating the suitability of MNR with adaptive management as a stand-alone sediment remedial strategy for Cottonwood Bay, located in Dallas, Texas. Current risks at the Cottonwood Bay site are associated with human consumption of fish contaminated with polychlorinated biphenyls (PCBs). The lines of evidence used to evaluate MNR included documentation of source control; review of PCB burial/isolation and surface sediment recovery; evaluation of sediment deposition and sediment stability; and demonstration of decreasing temporal trends in fish tissue PCB concentrations. The multiple lines of evidence demonstrated that source control and natural recovery processes have contributed substantially to reduced concentrations of PCBs and metals in surface sediments and PCBs in fish. MNR has been approved by the Texas Commission on Environmental Quality (TCEQ) and is incorporated as a stand-alone remedy in the revised Remedial Action Plan (RAP) for Cottonwood Bay. A long-term monitoring plan is being implemented as part of an MNR response action to confirm decreasing trends in surface sediment and fish fillet PCB concentrations over time and to demonstrate the continued effectiveness of natural recovery processes.