Background: Transient tachypnea of the newborn (TTNB) is a common cause of respiratory distress in late preterm and full-term infants. It is caused by a delay in the clearance of fetal lung fluids. Although TTNB is a self-limited condition, prophylactic antibiotics usually administered for 48-72 hours until negative blood culture is reported. Objective: In this study, we aim to identify the relationship between using prophylactic antibiotics and the duration of tachypnea and hospitalization in neonates with TTNB. Materials and Methods: this was a cohort study design included 102 infants with TTNB. The infants were divided into two groups, one received supportive care, and the other received supportive care with intravenous antibiotics. The clinical signs and laboratory results were examined in the two groups. Results: Of total 102 infants who were included in this study, 41 (40.2%) were received supportive care with prophylactic intravenous antibiotics. There were no significant differences between two groups in terms of gender, gestational age, birth weight, mode of delivery, and white blood cell. A significant relation was found between receiving prophylactic antibiotics with the duration of tachypnea and hospitalization. Conclusions: In the recent study, we found an increase in the hospitalization and tachypnea period in the group received antibiotics.