ICI 195,739, a novel orally active triazole, proved 50 times as potent as ketoconazole, produced a clinical cure, and completely eradicated residual infection in a murine model of pulmonary blastomycosis. No other previously tested azole has shown similar activity. Fungicidal activity against Blastomyces dermatitidis was seen in vitro at concentrations 1/40 of those achieved in serum with protective doses.