The virulence of two products of the fungus Beauveria bassiana (LCPP and Bassianil) on adult Anastrepha ludens (Loew) (Diptera: Tephritidae) and their effect on the mating performance of infected males was evaluated in laboratory and field cage tests. The horizontal transmission capacity of the fungus during copulation or attempted copulation also was quantified using inoculated males as well as the impact of infection on female fecundity and longevity. Both fungal products were found to be highly virulent (LCPP, mortality = 98.7% at 1 × 10⁸ conidia per ml, LT₅₀ = 4.20 d, LC₅₀ = 9.35 × 10⁵ conidia per ml; Bassianil, mortality = 99.3% at 1 × 10⁸ conidia per ml, LT₅₀ = 4.04 d, LC₅₀ = 2.69 × 10⁷conidia per ml). Mating success of inoculated males was not affected compared with the control group during the 3 d postinoculation. Horizontal transmission to females during the first day was 80.6 and 84.3% through mating and 15.4 and 21.6% through attempts to mate and contact during courtship for the LCPP and Bassianil products, respectively. The fertility of infected females was notably reduced, and longevity did not extend beyond 15 d. Our results suggest the possibility of using sterile flies as fungus vectors in sterile insect technique programs, but the potential benefits and shortcomings of this approach require further investigation.