Geosequestration1 involves the capture (from power stations and other facilities) and storage of carbon dioxide for very long periods of time in underground geological formations. This article is concerned with key legal and regulatory issues associated with establishing and operating geosequestration projects in Australia. It highlights the recent increased interest in, and raised profile of, using geosequestration as a greenhouse gas abatement measure in Australia. It reviews the cooperative efforts of the States, Territories and the Commonwealth to develop a nationally consistent regulatory framework for geosequestration projects, using existing petroleum legislation. These efforts have been driven by a lack of existing Australian legislation that provides an adequate and discrete regime dealing with the issues of responsibility and liability for geosequestered gas, although the release of draft legislation in this area is now imminent. It assesses some State legislative attempts to allow for the underground storage of carbon dioxide, and argues that these fail to satisfactorily deal with the long term (indefinite) nature of the storage aspect of geosequestration projects. Finally, this article examines the States' and Commonwealth's powers to legislate in respect of the injection and storage of carbon dioxide.