We compared the in vitro pharmacodynamics of isavuconazole, voriconazole, and posaconazole against 92 clinical isolates from documented cases of invasive aspergillosis, mucormycosis, fusariosis, and phaeohyphomycosis. Whereas inhibitory and fungicidal concentrations of these triazoles were predictably similar with the exception of Mucorales, isavuconazole appeared to have improved pharmacodynamics against Fusarium solani.