Rhinocerebral mucormycosis is an invasive fungal infection initiated in the paranasal sinuses that frequently progresses to orbital and brain involvement. If recognized early, involvement is limited to the nasal cavity and paranasal sinuses. Diabetics in poor control are at greatest risk, however, any immunocompromised individual may be infected. The mainstays of therapy are reversal of immunosuppression, systemic amphortericin B, and surgical débridement. Survival has improved dramatically, yet deaths still occur if the infection is not recognized and not treated early in its course or if the source of immunocompromise is not reversible. Several case examples illustrate the clinical course of this unusual, but potentially fatal, fungal infection. Taxonomy, clinical presentation, diagnosis, and management of mucormycosis of the paranasal sinuses are reviewed in detail.