Control technology for dreissenid mussels (Dreissena polymorpha and D. bugensis) currently relies heavily on chemical molluscicides that can be both costly and ecologically harmful. There is a need to develop more environmentally neutral control tools to manage dreissenid mussels, particularly in cooler water. Carbon dioxide has been shown to be lethal to several species of invasive bivalves, including zebra mussels and Asian clams (Corbicula fluminea). We evaluated the effects of various treatment regimes [i.e., exposure duration and pCO2 (partial pressure of carbon dioxide)] on mortality, byssal thread formation and attachment, and narcotization behavior. The effects of elevated carbon dioxide on nontarget native freshwater mussel Lampsilis siliquoidea were also measured. Results of trials conducted at 12°C indicated that carbon dioxide exposure induced narcotization behavior and reduced attachment of zebra mussels within 24 h. An extended exposure duration (96 h) produced 80-100% mortality of zebra mussels, and was safe to juvenile L. siliquoidea mussels. The results indicate that carbon dioxide could be used in an integrated pest management program for dreissenid mussels