Despite improvements in diagnosis and treatment, infections are still a major cause of morbidity and mortality in children with febrile neutropenia. In the majority of febrile episodes, the source of infection cannot be defined. In this study, we aimed to identify the earlier predictors of bacteremia/fungemia and a useful cytokine to identify the source of infection and to discriminate the patients with culture-confirmed bacterial/fungal infection. The most sensitive cytokine was interleukin (IL)-10 and the most specific was IL-8 in predicting culture-confirmed cases. IL-8 had greater sensitivity and specificity in determination of gram-negative bacterial infections with a higher negative predictive value; therefore, IL-8 can be used particularly to rule out gram-negative bacterial infections. IL-6, IL-8, and IL-10 circulating levels were shown to be higher in cases of infection. Further studies are needed to recommend a routine practice for predicting culture-confirmed bacterial infections.