To date, over 2,000 U.S. military personnel deployed to Operation Iraqi Freedom and Operation Enduring Freedom have been diagnosed with leishmaniasis. Almost all infections have been cutaneous leishmaniasis (CL) caused by the parasite Leishmania major. In the absence of a vaccine or prophylactic drug, the only method of protecting deployed soldiers from leishmaniasis is to prevent infected sand flies from feeding on them. This can be achieved through i) use of personal protective measures (use of a DEET-containing insect repellent on the skin, wearing permethrin-treated uniforms and sleeping under a permethrin-treated insect bed net), or ii) killing sand flies through appropriate use of insecticides. In order to assist in the development of effective leishmaniasis prevention and control efforts in Iraq and Afghanistan, we instituted a sand fly surveillance program in 2003 whereby deployed preventive medicine units shipped sand flies to the Walter Reed Army Institute of Research (WRAIR). Once received at the WRAIR, representative sand flies were identified to species and tested for the presence of Leishmania parasites using a Leishmania-generic Real-time (fluorogenic) Polymerase Chain Reaction assay. In order to determine the species of parasite, sand flies testing positive with the Leishmania–generic assay were retested with species-specific assays and portions of the Glucose 6-phosphate isomerase (GPI) gene sequenced. To date, 162,890 sand flies have been collected. Based on our data, beginning in 2005 we began separating Sergentomyia (non-vectors) from Phelbotomus (potential vectors) prior to testing for Leishmania parasites. Results to date indicate that Sergentomyia have a much higher infection rate than Phlebotomus – we are currently determining the species of parasite present in these two groups of sand flies. The impact of these results on our ability to accurately assess the risk of leishmaniasis will be discussed.