The aim of this study was to determine the predictive value of serum interleukin-6 (IL-6), interleukin-8 (IL-8), mannose binding lectin (MBL), procalcitonin (PCT) and C-reactive protein (CRP) levels for bacteremia/sepsis (B/S) at the beginning of a febrile episode in children with chemotherapy-induced febril neutropenia (FN). In a prospective study, 54 febrile neutropenic episodes from 30 pediatric cancer patients were analysed. Samples were obtained in two different clinical periods: afebrile neutropenic (AFN) period after chemotherapy and FN period (on the first day of fever). The highest levels of IL-6, IL-8, MBL and PCT were observed in cases of B/S group. However, only IL-8 levels were significantly higher in patients with B/S than those with clinically or microbiologically documented infection and those with fever of unknown origin (p<0.05). While sensitivity was high for IL-6 and IL-8, specificity value was found to be quite low. The marker with the highest specificity values was PCT. While positive predictive values of all markers were generally low, their negative predictive values were higher. The high levels of IL-8 are more reliable than the levels of IL-6, MBL, CRP and PCT for prediction of B/S in pediatric cancer patients with FN. With the combined use of inflammatory markers and cytokines, the low-risk group for B/S can be determined more clearly in patients with FN at the beginning of the febrile episode.