Solid-state C-13 NMR experiments were performed under uniaxial deformation of natural rubber to investigate the changes in the structural and dynamical behavior of the amorphous region induced by elongation. The structural change was detected as the change in the C-13 crosspolarization (CP) chemical shifts and line shapes. In addition, change in the CP 13C peak intensity as a function of time was also observed and was used to monitor the change of the dynamical behavior with time in high resolution. The relationship between 13C CP intensity and molecular dynamics under uniaxial deformation of natural rubber was examined by the H-1 magnetization decay behavior in the rotating frame and H-1-C-13 CP build-up curves. Although the strain-induced crystallization occurred at around 200% strain, the C-13 lineshapes showed no significant change in the orientation of the amorphous chains. On the other hand, the molecular dynamics of the amorphous chains was greatly affected even under lower extension, that is, the enhanced mobility of the chains was observed at 30% strain. This enhanced mobility induced by deformation decreased after the deformation was stopped. (C) 2003 Elsevier Ltd. All rights reserved.