Traditionally, the problem of invasive species, along with the decision-making framework established to prevent their introduction and spread, has been the domain of the biological scientific community. However, the scientific community is now calling for input by economics and other social science disciplines. The economic dimension of the problem of invasive species is growing from at least two perspectives. First, there is a greater awareness that economics is central to the causes of biological invasiveness, and that the consequences of pest incursions go far beyond direct damages or control costs. Second, modeling the economic and trade impact of regulations to combat the increased incidence of exotic pests and diseases, is becoming more important. This paper discusses the problem of invasive species from an economic perspective. It focuses on what economics has to do with the problem of biological invasiveness, and how the discipline can contribute to improving the decision-making framework.