SummaryCongenital Diaphragmatic Hernia (CDH) is one of the most common congenital abnormalities. Children born with CDH suffer a number of co-morbidities, the most serious of which is respiratory insufficiency from a combination of alveolar hypoplasia and pulmonary vascular hypertension. All children born with CDH display some degree of pulmonary hypertension, the severity of which has been correlated with mortality. The molecular mechanisms responsible for the development of pulmonary hypertension in CDH remain poorly understood. Ang-1, a central mediator in angiogenesis, participates in the vascular development of many tissues, including the lung. Although previous studies have demonstrated that Ang-1 may play an important role in the development of familial pulmonary hypertension, the role of Ang-1 in the development of the pulmonary hypertension associated with CDH is poorly understood. Here we report that Ang-1 appears important to murine lung development, establishing its tissue-level expression and localization patterns at key timepoints. Additionally, our data from a nitrofen/bisdiamine-induced murine model of CDH suggests that altered expression patterns of Ang-1, its receptor, Tie-2, and one of its transcription factors, Epithelium-specific Ets transcription factor 1 (ESE-1), may be responsible for the development of pulmonary hypertension in the setting of CDH.