Bronchopulmonary dysplasia is a chronic lung disease that develops in low-birth-weight infants as a result of mechanical ventilation and oxygen toxicity in the early neonatal period. In these patients, mechanical ventilation and oxygen support are needed for a long time. We already use antenatal steroid, ventilation techniques with minimal baro/volutrauma, postnatal steroid, and vitamin A to prevent the development of bronchopulmonary dysplasia. Mesenchymal stem cell treatment is another way to reduce or stop the pathophysiologic pathways in the development of bronchopulmonary dysplasia. Herein, we present mesenchymal stem cell treatment and its outcomes in twins who were born with a gestational age of 26 weeks and diagnosed as having bronchopulmonary dysplasia (the female twin was born with a birth weight of 750 g and the male twin was born with a birth weight of 930 g). These patients were followed up with clinical findings, chest radiography, and lung ultrasonography.