Abstract: OBJECTIVE:Patent ductus arteriosus is a common problem frequently encountered in preterm infants. We aimed to study the risk factors associated with reopening of patent ductus arteriosus and their short term outcomes in preterm infants. METHODS:A total of 162 preterm infants born between November 2013 and December 2015 with gestaional age less than 32 weeks and treated for hemodynamically significant patent ductus arteriosus are included in our study. RESULTS:113(69.8%) showed permanent closure and 49(30.2%) infants revealed symptoms of reopening after effective closure of patent ductus arteriosus. Low birth weight and small gestational age were more common in reopening group. Multivariete analysis showed that sepsis and multiple courses of drug treatment were independent factors affecting reopening of hemodynamically significant patent ductus arteriosus (OR: 3.01, 95% CI 1.48–6.13, p = 0.002) and (OR: 2.67, 95% CI 1.23–5.82, p = 0.013) respectively. Reopened group had a remarkable higher rate of developing necrotising nnterocolitis, bronchopulmonary dysplasia and retinopathy of prematurity than the closed group. (16.3% vs 4.4%, p = 0.01, 55.1% vs 28.3%, p = 0.001 and 55.1% vs 23.0%, p = 0.0001 respectively). CONCLUSION:Late neonatal sepsis and the need of multiple drug courses to close patent ductus arteriosus are risk factors affecting the reopening of patent ductus arteriosus in preterm infants.