Entomopathogenic fungi and eugenol have demonstrated great potential against ticks, particularly cattle tick Rhipicephalus microplus. In a pioneering study, Beauveria bassiana sensu lato (s.l.) CG 479 and eugenol were combined to assess their impact on the lipid profile and ovarian morphology of R. microplus. Germination tests revealed that regardless of concentration, the combination of B. bassianas.l. at 1 × 106 conidia ml-1 with eugenol at 0.18 mg ml-1 or 0.75 mg ml-1 exceeded 98%. Next, the engorged females were exposed by dipping to both agents individually or in combination. B. bassianas.l. combined with both eugenol concentrations reduced the reproductive parameters by 50%. For histopathology, tick females were exposed to fungus and eugenol, either alone or combined. The ovaries were extracted at 24 or 72 h and stained with hematoxylin and eosin. Groups exposed to the agents showed several modifications, including vacuolization of the pedicel and disorganization of the cytoplasm. The ovaries were also removed to determine the lipid profile by thin-layer chromatography. After 72 h of exposure, B. bassianas.l. combined with eugenol affected the levels of fatty acid and cholesterol. Furthermore, the reproductive parameters of the ticks were affected, which may explain the changes observed in the ovaries of R. microplus engorged females treated with both agents (combined or not). This study demonstrated the potential of combining entomopathogenic fungus and eugenol as a complementary strategy for managing cattle ticks.