Monitoring sand flies in the cutaneous leishmaniasis foci Kfar Adummim and Ma'ale Adummim from May to October generally yielded several hundred specimens per CO₂ baited trap. In the summer of 2009, a sharp rise in the number of sand flies trapped was recorded in Kfar Adummim, while numbers were similar to previous years in Ma'ale Adummim; approximately 4,000 specimens compared to about 400, with maximal catches of about 16,500 specimens in Kfar Adummim. We postulate that the sharp increase in sand fly numbers is directly related to the intensive construction conducted which enhanced sand fly breeding habitats.