The salt marsh mosquito Ochlerotatus vigilax occurs seasonally in high pest numbers adjacent to the Darwin urban area. They breed primarily in the upper tidal zone in the nearby Leanyer swamp after inundation by extreme tides and rain. The historic Leanyer Air Weapons Range (LAWR) created a 90ha area of bomb craters, which were very productive breeding sites for Oc. vigilax. The Medical Entomology Branch (MEB) with support from the Mosquito Control Advisory Committee, has long urged the rectification by filling and levelling of the bomb craters. The Department of Defence commissioned the rectification of the LAWR in June 1998 at a projected cost of $1.7 million. The major engineering works were carried out between May and June 2000. The area in the vicinity of the LAWR requiring insecticide control reduced from an average of 82.7ha before to 8ha after rectification. The reduction in Oc. vigilax breeding is presented spatially and temporally through a Geographic Information System. The rectification of the LAWR is a success story for the Department of Health and Community Services, the Mosquito Control Advisory Committee and the Department of Defence, with significant benefits to the people of Darwin.