Paediatric pulmonary hypertension has been described as a secondary complication of multiple diseases and their treatment. Limited information exists about the relationship between pulmonary hypertension and cancer in children. A review of charts was performed in all patients treated for cancer and developed pulmonary hypertension. A total of four patients developed pulmonary hypertension during treatment of cancer. All patients had solid tumors, had echocardiographic evidence of elevated right ventricular pressures, and required intensive care stays. Treatment courses included inhaled and oral pulmonary vasodilators along with systemic steroids. Each had normalisation of echocardiograms and resolution of pulmonary symptoms. Prompt diagnosis of pulmonary hypertension and treatment with pulmonary vasodilators and steroids are considered important measures followed by chemotherapy and radiation regimens.