The abundance, population structure, and Leishmania infection rates of Phlebotomus papatasi were studied at two villages, a 10-yr old date plantation, and an undisturbed natural habitat in the Jordan Valley throughout one season. On 109 trap nights in the villages, 53 female and 61 male P. papatasi were caught, whereas in burrows in the natural and agriculturally modified habitat, greater than 3,500 sandflies were trapped on 157 trap nights. Burrows in the data plantation produced larger numbers of males and females significantly more frequently than burrows in the natural habitat. The sex ratio in the natural habitat and the date plantation was significantly male biased. Parous rates were similar among habitats, whereas gravid females were significantly more active in the modified habitat. Leishmania infected females were not collected in the villages, yet close to 10% of females collected in the two other habitats were infected. Risk of transmission to humans in the villages was negligible, but people working in the date plantation were exposed to Leishmania infected sandflies.