An Australian Quarantine Inspection Service (AQIS) officer advised the Medical Entomology Branch (MEB) of Territory Health Services (THS) at 2pm 2 March 2000, of the detection of mosquito larvae in cargo ex Dili, East Timor which appeared to be Aedes aegypti. A sample of collected larvae were examined by an MEB entomologist at the AQIS office at 2.30 pm and he confirmed that they were Ae. aegypti. There were 5 freshly killed late fourth instar larvae. The Northern Territory is currently free of Ae. aegypti but the species is present in Queensland and countries to the north of Australia. This is the second instance of importation of an exotic Aedes species into Darwin in two months, with the previous importation of Aedes albopictus occuring in late January 2000.