Background: Antibiotics should be used to treat bacterial infections, while prescribing antibiotics for viral infections is ineffective. Sometimes, physicians do not diagnose diseases correctly and misdiagnose viral infections as bacterial. Objectives: In this study, we aimed to evaluate the appropriateness of prescribed antibiotics in the Children’s Emergency Department of Mofid Hospital, Tehran, Iran. Methods: This cross-sectional study was conducted in the Emergency Department of Mofid Children's Hospital during January-December 2019. All children younger than 16 years who were hospitalized and received antibiotics were included in this study. The degree of fever, diagnosis of disease, and laboratory findings were assessed. Results: We found 12.6% (38/301) inappropriate antibiotic prescriptions in the studied cases. The causes of antibiotic inappropriateness were incorrect diagnosis in 4.31% of patients (13/301), incorrect medication dose in 1.99% (6/301) patients, and no indication for the prescribed medicine in 6.31% (19/301) patients. Erythrocyte sedimentation rate, C-reactive protein, and neutrophil count were not significantly different between the two groups (P > 0.05). Conclusions: According to our results, incorrect antibiotic prescription is common in Mofid Hospital. Therefore, it is an urgent need to monitor and train the treatment system.