This is a non-comparative, open label study to evaluate the efficacy, safety and toleration of voriconazole in the treatment of invasive fungal infections. This agent will be used as primary therapy in those fungal infections in which no antifungal agent is currently approved or in patients unable to tolerate the approved agent. Voriconazole will also be used as a secondary treatment in those patients who have failed therapy with the primary approved agent or are unable to tolerate that agent or have unacceptable toxicity.