Previous works in this series3), 4) have shown the lowering in the order of cellulose by graft polymerization of methyl acrylate (MA) onto rayon filament. The present investigation was undertaken to clarify whether the orientation of cellulose is changed by graft polymerization of MA onto rayon filament.Samples used in this work were prepared by the same method as that presented in the previous papers3), 4). Samples grafted under swollen state are designated A-sample and those under unswollen state as B-sample respectively. Results obtained are as followings:(1) It is expected that the area of the cross section of grafted filament increase linearly with the amount of polymer grafted, but the observed area is larger than the expected in the region of high content of grafted polymer. Those results suggest the disorientation of the cellulose chains by grafting.(2) X-ray counter curve along the diffraction ring is flattend by grafting.(3) The dichroic ratio of the filament decreases by grafting. The difference between A and B samples in dichroism is not recognized. Then the decrease in the modulus by grafting is attributed not only to the disordering of structure, but also to the disorientation. The difference between modulus of A and B-samples previously reported4) arise from the difference in the order of cellulose, because the degree of disorientation by grafting indicates no difference between A and B-samples.