Cross-link densities in dynamically cured thermoplastic vulcanizates of polypropylene and ethylene-propylene-diene rubber (EPDM) were studied by analyzing the line broadening in single 90° pulse H magic-angle spinning (MAS) experiments. In a similar system, qualitative assessments of the cross-link density were made by using different models along with crosspolarization (CP) curves obtained from 1 H-13 C CP-MAS experiments. In all these latter approaches, the measured results depend upon the through-space orientationdependent H-1 H (or 1 H-13 C) dipole-dipole interaction, which reports on the cross-link density specifically. In a polymer, the spins exhibit a residual dipolar coupling (Dres) due to the presence of constraints like entanglements, cross-links, crystallites, etc. that cause incomplete averaging of segmental motions. Dres of protons measured under low-resolution conditions has been long used as a measure of cross-link density, and is connected to the dynamic order parameter (Sb) of the polymer backbone as: