In vitro interactions of givinostat, a hydroxamate-derived histone deacetylase inhibitor, and antifungals including itraconazole, voriconazole, posaconazole, amphotericin B and caspofungin against Aspergillus spp. were assessed via broth microdilution checkerboard technique system. A total of 30 isolates of Aspergillus spp., including 20 strains of A. fumigatus and 10 strains of A. flavus were studied. The results revealed favorable synergistic effects between givinostat and posaconazole (83.3%) against Aspergillus isolates. Limited synergism was observed when givinostat was combined with itraconazole or voriconazole. No interaction was observed between givinostat and amphotericin B or caspofungin. No antagonism was observed in all combinations.