Sulfur-crosslinked EPDMs were examined by ¹H pulsed NMR. Spin-spin relaxation time (T₂) was measured by Hahn echo method. The decay curve was resolved into two components, T_2n and T_2nn, which were arising from network molecules and non-network molecules, respectively. For unfilled EPDMs prepared at varying sulfur content, the higher order structures analyzed by Hahn echo method were almost the same as those analyzed for peroxide-crosslinked EPDMs. The reciprocal of Ten measured at 150°C for unfilled EPDMs increased linearly with increase in apparent crosslinking density (ν_s) values determined by modified Flory-Rehner equation. For EPDMs filled with carbon black (CB), the crosslinking density of rubber phase (ν_R) was calculated from the relationship between ν_s and 1/T_2n for unfilled EPDMs. The crosslinking density related to CB (ν_F) was obtained from the difference between the ν_s and ν_R. The ν_F values showed good correlation with the tensile stress at 100% elongation, independent of the kinds of cure agents.