The Florida Keys Mosquito Control District has conducted larvicide missions on uninhabited offshore islands of the Great White Heron National Wildlife Refuge and the National Key Deer Refuge since 2003. The objective of these missions is to reduce the need to apply adulticides on nearby populated islands where private lands are interspersed with refuge lands that support a diverse assemblage of native butterflies and insect-pollinated plants on Big Pine Key, No Name Key, Little Torch Key, Middle Torch Key, and Big Torch Key (the Torch Keys). More than 800 visits were made to refuge islands by Florida Keys Mosquito Control District personnel; 334 aerial larvicide missions were flown. From 2003 to 2010, a marked reduction in adult mosquito numbers was seen on Big Pine Key, and to a lesser extent on No Name Key. Seasonal distribution of mosquitoes was not different, however. Number of aerial adulticide missions flown on Big Pine Key, No Name Key, and the Torch Keys was 2, 1, and 2 in 2003; 9, 10, and 7 in 2004; 4, 4, and 2 in 2005; 6, 6, and 7 in 2006; 1, 0, and 0 in 2007; 3, 2, and 4 in 2008; 4, 3, and 4 in 2009; and 1, 1, and 3 in 2010, respectively. This is a dramatic reduction from prior years; from 1998 to 2002, 57 aerial adulticide missions were flown on Big Pine Key, 45 missions were flown on No Name Key, and 38 on the Torch Keys. Larviciding is an important component of an integrated approach to mosquito management that seeks to reduce environmental impacts on the national wildlife refuges.