Febrile neutropenia (FN) is one of the side effects caused by chemotherapy due to hematopoetic suppression that cause neutropenia and other triggerring factors such as infection. More specifically, FN is defined as the temperature above 38,3oC at once oral temperature measurements or 38,0oC temperature within a period of time more than one hour with neutrophil counts less than 500/mm3 or neutrophil counts less than 1000/mm3 with predicted decline to 500/ mm3 within 48 hours. Febrile neutropenia defined as a medical emergency and oncology which has a high mortality rate. Although currently there is a great development in the prevention and therapy of FN, but this is still the most feared complication of cancer chemotherapy. This article summarizes the important aspects of the FN as well as it's early detection and management that should be of concern for clinicians who decide to use chemotherapy as one of treatment modality for their patients.