Beauveria bassiana (Bals.-Criv.) Vuill. and Metarhizium anisopliae (Metchnikoff) Sorokin were autodisseminated in the house fly, Musca domestica L., when one, five, and 10 virgin, 3-day old males exposed to 6 × 10⁸ conidia ml^-1 per fungus were confined with 30 females of the same age. Fungal treatments with one or five males killed few, with LT₅₀ of 7 and 5 days, respectively, but when 10 funguscontaminated males were placed with 30 flies, LT₅₀ was 3 days with a sporulation rate of 94% and 66% less oviposition. Moreover, confinement of one, five, or 10 fungal-infected males caused an incremental increase in virulence, reducing the LT₅₀. The regression of the mean of eggs, first-instar larvae, and days of gonotrophic cycle on the LT₅₀ values of nine treatments (six fungal groups and three checks) showed that the three variables decreased about 3–4 units per unit of LT₅₀. Likewise, when the gonotrophic cycle time was regressed on mean oviposition, a linear equation demonstrated that for each decrease of 15 eggs, the gonotrophic cycle was 1 day shorter, which was shortened from 7 days in healthy flies to 2 in females of the fungal treatment with 10 males. Ten virgin males impregnated with spores of either fungus infected and killed 50% of the exposed females in 3 days. This autodissemination could be used to improve integrated control of M. domestica in the field and human environments.