In northern Tunisia 29 sandfly collecting places were studied for two years, in five human leishmaniasis foci, seven canine foci and in the nature. Nine species were found among the 4942 specimens collected. P. perniciosus, the well known vector of visceral leishmaniasis and the herpetophile S. minuta parroti were commonest. The sandfly season extended from april to october. P. perniciosus showed a numerical curve with one peak. It occupied various types of shelters in nature and human settlements, but prefer shady and humid shelters. In settlements it is frequently found around dwellings and has been identified in human and canine leishmaniasis foci. The highest sandfly densities and greatest species diversity were noticed in towns, especially in the cracks of the old walls or old inhabited ruins, where rodents as well as the small domestic animals provide a favourable environment for the sandflies. The historical urban ruins are the main biotope of the sandfly vectors. Infantile visceral leishmaniasis occurs during summer when the children sleep in front of the houses or in large, opened rooms exposed to P. perniciosus flies which have bitten infected dogs.