Purpose The study was aimed to evaluate the effect of uric acid (UA) on the 30-day mortality of patients admitted to the tertiary referral hospital with a complaint of febrile neutropenia (FEN). The secondary aim was to evaluate the use of combining serum UA levels with the Multinational Association for Supportive Care in Cancer (MASCC) risk score. Methods A retrospective study in which the MASCC score and serum UA levels were used to evaluate the mortality risk within 30 days among patients with FEN. Results A total of 118 FEN episodes were included in the study and 17 (14%) of these patients died. While this rate is 23% in the high-risk group according to the MASCC score, it is 7% in the low-risk group (p = 0.011). In multivariate analysis of the parameters that significantly affect the 30-day FEN mortality, MASCC risk score (OR, 4.28; CI 95% 1.19-15.39,p = 0.013) and having a level of serum UA > 7 mg/dL (OR, 4.46; CI 95% 1.19-15.38,p = 0.032) was significantly increased the risk of in 30-day mortality of FEN. The rate of 30-day mortality of FEN was 0% in patients with a low MASCC risk score and UA level compared with 50% in the high MASCC risk score and high UA level group, and the difference was statistically significant (p < 0.001). Conclusion Increased level of UA at the time of FEN diagnosis was independently associated with an increased rate of 30-day mortality of FEN. The combination of the MASCC risk score and serum UA level might thoroughly predict the 30-day mortality of FEN.