Details are presented of a project in which Megarhyssa nortoni was released in an attempt to control Sirex noctilio. Logs [of Pinus radiata] infested with M. nortoni were distributed in Sirex-infected [Pinus radiata] plantations throughout the SE region (143 release sites) of the South Australia Woods & Forests Department during October 1988. An estimated 18 000 female M. nortoni emerged from these logs from October to December. Releases of other parasitoids (Rhyssa hoferi, R. persuasoria and Schiettererius inctipes) of Sirex noctilio were not practical, because densities of these species were too low. The project was considered successful, and it is recommended that strategies for releasing parasitoids should include log transport in addition to the release of adult parasitoids obtained from either insectary cultures or field-collected logs. none