Pulmonary Agenesis (PA) is a rare congenital malformation of lung development, and patients with comorbid Pulmonary Hypertension (PH) have substantially increased morbidity and mortality risks. We describe five pediatric cases born with unilateral PA who developed PH. By integrating our findings with those of 7 previously published case reports, we aim to provide a more complete description of disease features, prognosis, and the most effective treatment strategies. We found that male PA patients and those with right-side agenesis were more likely to develop PH. Moreover, half of these comorbid patients had congenital heart disease with left-to-right shunt. Early diagnosis and treatment, including surgical and medical interventions, are critical for preservation of cardiopulmonary function. All PA cases should receive regular cardiopulmonary function tests starting at an early age.