A stenosis in one of the pulmonary branches affects the hemodynamics of the pulmonary circulation. It causes an unequal flow distribution over the right and left lung and increases the pressure load of the right ventricle (RV). On top of that, a stenosis may disturb the normal, laminar flow of blood. It is thought that the abnormal flow caused by a stenosis contributes to diminished cardiovascular functioning on the long-term. To improve our understanding of the hemodynamic impact of a stenosis, it is important to extensively study flow patterns and hemodynamic parameters. This thesis describes the hemodynamics of pulmonary artery (PA) stenosis in three compartments: in vivo, in silico and in vitro.