Rodents were collected from endemic foci of cutaneous leishmaniasis in Jordan, either by flooding their burrows with water or using Sherman traps. Of the 170 jirds (Psammomys obesus) collected, 39 (23%) had Leishmania amastigotes in one or both ears. Although cultures of ear biopsies from the infected animals were all positive, cultures made using biopsies from their noses, livers or spleens were all negative. The infected jirds were encountered in seven of the nine areas studied. Biochemical characterization of six isolates from P. obesus, using cellulose acetate electrophoresis of six enzymes (glucose-6-phosphate dehydrogenase, 6-phosphogluconic dehydrogenase, malic enzyme, phosphoglucomutase, phosphoglucoisomerase and fructokinase) showed that the jird isolates were isoenzymatically identical with two Jordanian human Leishmania isolates and reference isolates of L. major but differed from reference strains of L. tropica. None of the other rodents caught (Meriones libycus, M. crassus, M. tristrami, Allactaga euphratica and Gerbillus spp.) yielded Leishmania parasites, confirming that P. obesus is the major reservoir host of cutaneous leishmaniasis in Jordan.