Introduction: Multi-detector pulmonary CT angiography is now the first line of investigation in the diagnosis of most of the pulmonary vascular disorders. The increase in gantry speed and thinner collimation that accompanied the introduction of multidetector CT scanners has extended the accuracy of assessment of the pulmonary vasculature to the subsegmental level. Purpose: The aim of this study is to demonstrate the role of MDCT pulmonary angiography in the diagnosis of different pulmonary vascular disorders. Patients and methods: 50 patients were examined using a 4-multidetector CT scanner in the radiology department in Cairo University. The study population was divided into 3 groups. Group A including 29 patients clinically suspected with pulmonary embolism. Group B including 12 patients diagnosed with pulmonary hypertension upon echocardiographic basis. Group C including the last 11 patients having other pulmonary vascular disorders as pulmonary artery aneurysms, congenital anomalies and pre-operative assessment of neoplastic lesions. Results: Group A showed 69% of the patients having pulmonary embolism and 27.5% showing embolic filling defects at the subsegnmental level. Group B showed dilated pulmonary artery in all patients, right ventricular enlargement in 33.3% of cases, and dilated bronchial and non-bronchial vessels in 25% of cases. Group c showed a variety of other pulmonary vascular disorders as pulmonary artery aneurysms, congenital absence of the pulmonary artery, Macleod’s syndrome, pulmonary AVM (showing the hypertrophied deeding vessels), and pre-operative assessment of a neoplastic hilar mass shown to be irresectable. Conclusion: MDCT pulmonary angiography is a relatively available, minimally invasive investigation that can now be considered as the first line of investigation in diagnosis of pulmonary embolism with its ability to detect small emboli down to the segmental and subsegmental level. It is of value in patients with pulmonary hypertension as it shows different signs of pulmonary hypertension as well as the possible cause. In most cases of congenital anomalies and pulmonary aneurysms pulmonary CTA provides the needed data for management in such cases.