Door seals are usually designed to meet specific performance with respect to door closing energy. The static compression load deflection (CLD), given as the force required to compress 100mm length of seal, is generally used as a measure of performance of seal compression. The CLD is always specified as a quasi-static stiffness characteristic. However a door closure event is a complicated transient dynamic impactloading phenomenon during which a seal is dynamically compressed due to door inertia and initial velocity. In this study, a method is developed to measure dynamic seal compression load deflection response (Dynamic CLD) which incorporates effects of door mass and speed. Dynamic CLD measurements were carried out at several sections in a production vehicle door sealing system using the developed method. Seal compression energy predictions were then compared to door closure energy results measured on the vehicle.