The objective of this study was to assess interactions between mixtures of a strain and two native isolates of Metarhizium anisopliae Sorokin on yellow fever mosquito, Aedes aegypti (L.). Twenty-five third-instar larvae were put into 200-ml plastic containers with 135 ml of sterile double-distilled water and 15 ml of inoculum of each fungus (HIB-11, HIB-12, Ma) tested alone and in combination (HIB-11 + Ma, HIB-12 + Ma). Sterile double-distilled water (135 ml) and 7.5 ml of inoculum of each fungi in the combined treatment had 15 ml of inoculum per each dual treatment. Interaction between the isolates and M. anisopliae strain was additive, which was not observed in the lowest concentration because of an antagonistic effect at that level.