Up until summer 2002, only one invasive aquatic plant species, variable water-milfoil (Myriophyllum heterophyllum), had been documented in Maine waters. Since then, however, two invasive aquatic plants often cited as North America’s nastiest have shown up in two small ponds in southern Maine. Hydrilla (Hydrilla verticillata) was confirmed in fall 2002 and Eurasian water-milfoil (Myriophyllum spicatum) in fall 2004. This paper focuses on Maine’s response to the hydrilla infestation in Pickerel Pond, Limerick, Maine since the Eurasian water-milfoil work is only beginning as of this writing. Key components of Maine’s response to hydrilla are early detection, communication, containment, surveillance of neighboring waters, and control of the inpond plant population.