Laboratory and field efficacy trials comparing deet (N,N-diethyl-3-methylbenzamide) and SS220 [(1S, 2′S)-2-methylpiperindinyl-3-cyclohexen-1-carboxamide] against mosquitoes in Queensland, Australia, were conducted. In the laboratory, both compounds provided between 150 and 195 min of protection against Aedes aegypti and between 18 and 80 min of protection against Anopheles farauti. In laboratory tests against Culex annulirostris, 20% SS220 provided 3 h of protection and 20% deet provided >6 h of protection. A field efficacy test was conducted at Redcliffe, Queensland in January 2008 and the predominant mosquito species collected was Cx. annulirostris (84.4% of collection). In the field, 20% SS220 provided significantly better protection against mosquitoes than 20% deet. Seven hours after application, SS220 provided greater than 96.0% protection against all mosquitoes, whereas 20% deet provided 58.9% protection.