Background: Invasive fungal infections (IFIs) are of serious concern in the management of immunocompromised patients (pts) with hematological disorders. Empiric antifungal therapy is recommended for neutropenic pts with persistent fever, because treatment after confirmation of fungal infection often produces poor outcomes. Micafungin (MCFG), one of the echinocandin families, was launched first in Japan in 2002, and has now been approved in more than 11 countries and areas including the USA and the EU. Although the efficacy and safety of MCFG against both Candida and Aspergillus infections has been shown in many clinical trials, there are few clinical study reports on the empiric therapy of a suspected fungal infection. Here, we report the multi-center study results of MCFG for the empiric antifungal therapy, which were conducted from April 2005 to September 2006 in Japan. Objective: This prospective study was performed to clarify the efficacy and safety of MCFG for the empirical antifungal therapy on suspected fungal infection in pts with hematological disorders and neutropenia. Methods: Study design: A multiple-center, open, uncontrolled study. The investigator registered pts with neutropenia (