The term mucormycosis encompasses a distinctive group of infections caused by fungi belonging to genera within the taxonomic order Mucorales, usually Rhizopus, Absidia, Mortierella, and Mucor. These fungi are widespread in nature, subsisting on decaying vegetation and diverse organic materials. Although the fungi and spores of Mucorales show minimal intrinsic pathogenicity toward normal persons, they can initiate aggressive and fulminant infections under certain clinical conditions. Ketoacidotic diabetics are predisposed to rhinocerebral mucormycosis, whereas patients with leukemia or lymphoma are susceptible to pulmonary or disseminated infections. These infections, which often result in devastating long-term sequelae for surviving patients, pose difficult diagnostic and therapeutic challenges.