CDC miniature light traps were used to evaluate the general biology of phlebotomine sand ßies from April 2003 to November 2004 at Tallil Air Base, Iraq. Factors evaluated include species diversity and temporal (daily and seasonal) and geographic distribution of the sand ßies. In addition, the abundance of sand ßies inside and outside tents and buildings was observed. In total, 61,630 sand ßies were collected during 1,174 trap nights (mean 52 per trap, range 0 Ð1,161), with 90% of traps containing sand ßies. Sand ßy numbers were low in April, rose through May, were highest from mid-June to early September, and dropped rapidly in late September and October. More than 70% of the sand ßies were female, and of these sand ßies, 8% contained visible blood. Phlebotomus alexandri Sinton, Phlebotomus papatasi Scopoli, Phlebotomus sergenti Parrot, and Sergentomyia spp. accounted for 30, 24, 1, and 45% of the sand ßies that were identiÞed, respectively. P. alexandri was more abundant earlier in the season (April and May) than P. papatasi, whereas P. papatasi predominated later in the season (August and September). Studies on the nocturnal activity of sand ßies indicated that they were most active early in the evening during the cooler months, whereas they were more active in the middle of the night during the hotter months. Light traps placed inside tents with and without air conditioners collected 83 and 70% fewer sand ßies, respectively, than did light traps placed outside the tents. The implications of these Þndings to Leishmania transmission in the vicinity of Tallil Air Base are discussed.