Detection of underlying etiology of fever, particularly the discrimination of infection and inflammation during the posttransplant period of bone marrow transplantation (BMT), is of crucial importance for the proper management of transplant patients. To differentiate infections from inflammatory events, various laboratory parameters including procalcitonin (PCT), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) have been used to aid clinical evaluation. The aim of this prospective study was to evaluate the use of PCT, CRP and ESR in discrimination of fever etiology following BMT in children. Twenty consecutive children (14 male and 6 female) were enrolled in the study. Procalcitonin, CRP and ESR values were tested in each patient on day 0, in the first 6 hours of the first febrile episode and on day +20. Blood cultures were obtained at each sampling. The difference between the number of patients with elevated levels of ESR (100%) and of PCT (36%) was significant among the patients having mucositis (p=0.01). There was no significance among parameters in culture-positive patients (p=0.368). Among the patients having graft versus host disease (GVHD), none of the elevated parameters showed significant differences upon comperison (p=0.779). According to this cohort, ESR may be the most useful laboratory parameter in evaluating inflammatory events, while PCT has no superiority to CRP or ESR in the determination of septic or inflammatory events in bone marrow transplanted children. Anahtar Kelimeler : prokalsitonin, C-reaktif protein, eritrosit sedimentasyon hızı, kemik iliği transplantasyonu, procalcitonin (PCT), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), bone marrows transplantation (BMT), children