Introduction.Cryptococcusspecies are pathogens commonly associated with cases of meningoencephalitis in individuals who are immunosuppressed due to AIDS.Aim.The aim was to evaluate the effects of the antiretroviral darunavir alone or associated with fluconazole, 5-flucytosine and amphotericin B against planktonic cells and biofilms ofCryptococcusspecies.Methodology.Susceptibility testing of darunavir and the common antifungals against 12 members of theCryptococcus neoformans/Cryptococcus gattiispecies complex was evaluated by broth microdilution. The interaction between darunavir and antifungals against planktonic cells was tested by a checkerboard assay. The effects of darunavir against biofilm metabolic activity and biomass were evaluated by the XTT reduction assay and crystal violet staining, respectively.Results.Darunavir combined with amphotericin B showed a synergistic interaction against planktonic cells. No antagonistic interaction was observed between darunavir and the antifungals used. AllCryptococcusspecies strains were strong biofilm producers. Darunavir alone reduced biofilm metabolic activity and biomass when added during and after biofilm formation (P<0.05). The combination of darunavir with antifungals caused a significant reduction in biofilm metabolic activity and biomass when compared to darunavir alone (P<0.05).Conclusion.Darunavir presents antifungal activity against planktonic cells ofCryptococcusspecies and synergism with amphotericin B. In addition, darunavir led to reduced biofilm formation and showed activity against mature biofilms ofCryptococcusspecies. Activity of the antifungals against mature biofilms was enhanced in the presence of darunavir.