Invasive fungal infections due to Aspergillus calidoustus with decreased azole susceptibility are emerging in the setting of azole prophylaxis and are associated with poor outcomes. We assessed the in vitro activity of antifungal drugs used alone or in combinations against A. calidoustus and found a synergistic effect between voriconazole and terbinafine at concentrations within the therapeutic range. An invertebrate Galleria mellonella model of A. calidoustus infection tended to support the potential benefit of this combination.