Invasive fungal infections are occurring with increasing frequency secondary to medical advances in the areas of transplantation, cancer management and autoimmune diseases. Unfortunately, the currently available antifungal armamentarium does not meet the increasing needs of managing infection in these complex patient populations. Posaconazole, a new triazole antifungal agent, is being investigated for its role in treating serious infections due to yeasts and molds. This new drug offers an expanded spectrum of activity over other members of its class. In addition to potent activity against fluconazole-resistant Candida and refractory cases of aspergillosis, posaconazole demonstrates activity against Zygomycetes. Posaconazole is a well-tolerated agent that offers a diminished toxicity profile compared with other currently marketed systemic antifungal agents. Clinical success rates thus far have been promising, although the exact role of this agent in treating and preventing invasive fungal infections is yet to be determined.