Introduction: This study aims to determine the use of thiol/disulphide homeostasis parameters together with procalcitonin (PCT), C-reactive protein (CRP) and Multinational Association for Supportive Care in Cancer (MASCC) risk scoring system for the prediction of prognosis and mortality in the patients with febrile neutropenia presenting to the emergency department. Material and methods: The study was carried out prospectively on 53 patients with febrile neutropenia and 51 healthy subjects presenting to the emergency department. Thiol/disulphide homeostasis parameters, which are oxidative stress markers, were measured through a new method developed by Erel and Neşelioğlu. PCT and CRP were also measured. Patients were grouped in to high-risk and low-risk groups in terms of prognosis and mortality through MASCC scores. Results: Mean values of disulphide/native thiol, CRP and PCT were found to be significantly higher in the patients having febrile neutropenia (p=0.029, p<0.001 and p<0.001, respectively). Mean values of disulphide/native thiol, CRP and PCT were found to be significantly higher in the high-risk patients (p=0.038, p=0.004, and p=0.002, respectively). Conclusion: The use of thiol/disulphide homeostasis parameters, PCT and CRP together with the MASCC system may be used for the prediction of the prognosis in the patients with febrile neutropenia.