Sandßies collectedbetweenApril 2003 andNovember 2004 atTallilAirBase, Iraq,were evaluated for the presence of Leishmania parasites using a combination of a real-time Leishmaniageneric polymerase chain reaction (PCR) assay and sequencing of a 360-bp fragment of the glucose6-phosphate-isomerase (GPI)gene.A total of 2,505pools containing 26,574 sandßieswere testedusing the real-time PCR assay.LeishmaniaDNAwas initially detected in 536 pools; however, after extensive retesting with the real-time PCR assay, a total of 456 pools were considered positive and 80 were considered indeterminate. A total of 532 samples were evaluated for Leishmania GPI by sequencing, to include 439 PCR-positive samples, 80 PCR-indeterminate samples, and 13 PCR-negative samples. Leishmania GPI was detected in 284 samples that were sequenced, to include 281 (64%) of the PCR-positive samples and 3 (4%) of the PCR-indeterminate samples. Of the 284 sequences identiÞed asLeishmania, 261 (91.9%)wereL. tarentolae, 18 (6.3%)wereL. donovani-complex parasites, 3 (1.1%) were L. tropica, and 2 were similar to both L. major and L. tropica.Minimum Þeld infection rates were 0.09% for L. donovani-complex parasites, 0.02% for L. tropica, and 0.01% for the L. major/tropica-like parasite. Subsequent sequencing of a 600-bp region of the “Hyper” gene of 12 of the L. donovanicomplex parasites showed that all 12 parasites were L. infantum. These data suggest that L. infantum was the primary leishmanial threat to U.S. military personnel deployed to Tallil Air Base. The implications of these Þndings are discussed.