The Moroccan province of Al Haouz is an emerging focus of human cutaneous leishmaniasis caused by Leishmania tropica. In an entomological investigation of three communes in the province (Ourika, Stti Fatma and Rhmate), 3440 sandflies were collected on sticky traps in 2005-2007. Of the six Phlebotomus species caught, Phlebotomus papatasi (13.3% of the total collection), P. sergenti (12.8%) and P. perniciosus (12.8%) were predominant, followed by P. longicuspis (7.9%), P. ariasi (2.6%) and P. alexandri (1.1%). All the other sandflies were Sergentomyia fallax (24.2%), S. minuta (22.0%) or S. dreyfussi (3.4%). The distribution of these species among the many biotopes, at varying altitudes (667-1772 m), is discussed. When the variability of the P. sergenti populations in Ourika and Rhmate and those at two sites in northern Morocco (Taounate and Chefchaouene) was investigated by iso-enzyme analysis, seven polymorphic loci (PGI, PGM, HK, MDH1, ME, 6PGD and ACO) were identified. None of the investigated populations of P. sergenti was in Hardy-Weinberg equilibrium for all the polymorphic loci. The results indicate that the taxon known as Phlebotomus sergenti in Morocco does not have the genetic characteristics of a single species.