New importance has been given to zygomycosis, as what was uncommon is no longer. Zygomycosis (mucormycosis) typically occurs in patients with leukemia, with solid-organ transplants or bone marrow transplants, with diabetic ketoacidosis, in those who have received steroids or are neutropenic, and after desferioxamine therapy. Often, both diagnostic and therapeutic measures are performed too late and are inadequate. Mortality rates may be as high as 80% in infected transplant recipients. Zygomycosis also appears to have made a subtle increase in incidence: up to 8% in autopsied patients with leukemia, and 2% in allogenic bone marrow transplant patients. Most infections are acquired by inhalation, ingestion, or trauma. They rapidly infarct blood vessels, resulting in necrosis of surrounding tissue. Over the past few years, new diagnostic procedures, susceptibility tests, and drugs have entered the clinic, and these advances are discussed in the review. With the rise in number of cases of 'zygomycosis', new scrutiny has been directed at the terms 'zygomycosis' and 'mucormycosis'. This review explains their differences and the attending relevance for the clinician. Diagnostic methods include new molecular detection assays and new susceptibility testing options. New treatment options will soon exist with triazole antifungal agents. The first one expected to enter clinical practice is posaconazole in 2005. Its metabolism, pharmacokinetics, in-vitro and in-vivo activity, and clinical study results are described. Finally, we present our approach to zygomycosis. This review discusses key elements to laboratory diagnostic and susceptibility procedures and new treatment options.