Invasive plants are considered to be a major threat to the Earth's biodiversity. Such plants cost U.S. agricultural and forest producers billions dollars each year because of decreased productivity and increased costs of production for weed control. While considerable effort is being spent studying these exotic plant pests, little consideration has been given as to how invasive plants might react to the increasing concentration of CO₂ in the atmosphere. Tropical spiderwort (Commelina benghalensis L.) is considered one the world's most invasive weeds and is becoming more of a problem in agricultural settings of the southeastern US. Tropical spiderwort was grown under ambient and elevated levels of CO₂. Under elevated CO₂ conditions, plant organ parts exhibited significant increases in dry weight (leaf, 36%; flower,30%; stem, 48%) and the overall increase in total aboveground biomass was 44%. Total stem length was unaffected by CO₂ level while total leaf number and total flower number showed trends for increase (~20%) due to additional CO₂. The strong growth response of the invasive weed tropical spiderwort suggest that its competitive ability with native plants will be enhanced in a future high CO₂ environment.