Introduced species are a major threat to the planet's ecosystems and one of the major causes of species extinction. This study deals with some of the economic impacts of one of these "invaders," variable milfoil. Variable milfoil can clog water-bodies, cause boating and swimming hazards, and crowd out native species. This study analyzed the effects of variable milfoil on shoreline property values at selected New Hampshire lakes. Results indicate that property values on lakes experiencing milfoil infestation may be considerably lower than similar properties on uninfested lakes. Results are highly sensitive to specification (variable selection) of the hedonic equation.