For the study of time frequency of the principal vectors of the Mucocutaneous Leishmaniasis in the Ilha Grande (Great Island), from 1976 to 1977 we made four catches in 24 hours with animal bait (dog) in the outdoors and five catches in just one house of the area. It was found that the species Lutzomyia intermedia occurred during the whole night a steady density in human dwellings, while the species Lutzomyia migonei presented greater density at dawn, in catches with animal bait (dog). in a 156 hours' study on monthly variation, from March 1976 to February 1977, a specie Lutzomyia intermedia appeared during the whole year, the months of April, May, October and December being those of greater density while the specie Lutzomyia migonei had a low density even disappearing in September. The high densities of the species Lutzomyia intermedia and Lutzomyia migonei indica te them as the probable vectors of the mucocutaneous leishmaniasis in Ilha Grande.