Once-daily dose administration of aminoglycoside in adults is effective and economical. However, its value in febrile neutropenic children, especially in Thailand, is less well researched. In the area where Pseudomonas aeruginosa prevalence in febrile neutropenic children is low, the combination of cloxacillin and amikacin is an appropriate approach. This study would like to compare the efficacy and safety including cost between these two amikacin administrations (once-daily or twice-daily) in combination with cloxacillin as an empirical therapy in febrile neutropenic children.