Recently, empirical antifungal therapy with intravenous itraconazole (ITCZ) for neutropenic patients with antibiotics-resistant fever has been approved by Japanese Ministry of Health, Labour and Welfare on the bases of previous multicenter trials of foreign countries. In this study, we conducted a single-arm, multicenter, prospective study in order to evaluate the efficacy of empirical ITCZ injection on Japanese patients. Sixty-eight patients with hematological diseases who underwent anticancer chemotherapy or stem cell transplantation were enrolled. In this study, we found that the overall clinical response rate to ITCZ injection was 67.6% and success rate of achieving composite endpoints including survival, defervescence during neutropenia, no breakthrough fungal infections, and no premature discontinuation of drug was 50.0%. Mild adverse reactions were observed in 6 patients (8.8%). Further analysis revealed that possible/probable deep fungal infection according to the 2002 and 2008 criteria defined by EORTC/MSG were found in 19.1 and 7.5% of the patients, respectively. Interestingly, response rate to ITCZ injection of possible/probable cases according to the 2002 and 2008 criteria was 61.5% (8/13) and 100% (5/5), respectively. These results not only proved the good efficacy and safety of empirical ITCZ injection for Japanese patients, but also indicated a utility of the drug on future "presumptive" approach.