Invasive fungal infections (IFI) can cause serious morbidity and mortality among febrile patients with chemotherapy-induced neutropenia (CIN). In order to evaluate the incidence, treatment outcome and factors associated with IFI in this patient population in Thailand, we retrospectively reviewed the medical record of patients admitted to Siriraj Hospital from January 2008 to June 2010. Criteria used to diagnosed IFI were those of the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases/Mycoses Study Group (EORTC/MSG) consensus 2008 criteria. Three hundred ten episodes of chemotherapy-induced neutropenia occurred in 233 patients. IFI were found in 37 episodes (12%) and occurred only in patients who received chemotherapy for hematological malignancies. The incidence of IFI among patients with hematologic malignancies was 14%. Most commonly occurred in AML patients (17%). Patients who received aggressive induction chemotherapy regimens for AML had the highest incidence of IFI (20.5%). Of the 37 episodes, 12 were candidiasis, 5 were aspergillosis, 1 was zygomycosis, 1 was fusariosis, 10 were probable and 9 were possible IFI. The IFI-related mortality was 35%. The clinical factor associated with IFI was a temperature >39 degrees C during febrile neutropenia. A higher mortality rate was seen in patients aged >40 years and those with a serum albumin level < 3 g/dl.