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<i>Forcipomyia taiwana</i> (Diptera: Ceratopogonidae) is a nuisance blood-sucking pest to humans in Taiwan. An <i>F. taiwana</i> bite causes itching and redness and usually causes serious harassment to human outdoor activity. In terms of <i>F. taiwana</i> control, chemical pesticides are ineffective. Therefore, other efforts are needed. Fungal mycosis in the larvae, pupae, and emerging <i>F. taiwana</i> adults was found during the rearing of <i>F. taiwana</i>. In this study, six fungal isolates were isolated from infected cadavers and subjected to molecular identification. In addition, their biocontrol potential was evaluated against different life stages of <i>F. taiwana.</i> Based on the pathogenicity screening, two fungal isolates, NCHU-NPUST-175 and -178, which caused higher mortality on the fourth instar larvae of <i>F. taiwana</i>, were selected for virulence tests against different life stages of <i>F. taiwana</i> larvae. The results of the phylogenetic analysis indicated that the NCHU-NPUST-175 and -178 belonged to <i>Purpureocillium lilacinum</i> and <i>Fusarium verticillioides</i>, respectively. Bioassay against different life stages of <i>F. taiwana</i> with different spore concentrations (5 × 10⁵ to 5 × 10⁷ conidia/mL) revealed a dose-dependent effect on larvae for both fungal isolates, while only 38% and 50% mortality was found in highest concentration (5 × 10⁷ conidia/mL) at fourth instar larvae by Pl-NCHU-NPUST-175 and Fv-NCHU-NPUST-178, respectively. Moreover, reductions in egg-hatching rate and adult emergence rate were found, when the last stage of <i>F. taiwana</i> was inoculated with both fungal isolates, indicating the ovicidal potential and the impact of entomopathogenic fungi on the development of <i>F. taiwana</i>. In conclusion, Pl-NCHU-NPUST-175 and Fv-NCHU-NPUST-178 showed larvicidal activity, ovicidal activity, and impact on adult emergence on <i>F. taiwana</i>.