Vacuum ultraviolet (VUV) photodissociation of CH3OH and CH3OD at 121.6nm was studied using high-n Rydberg atom time-of-flight (HRTOF) technique. The H-atom product TOF spectrum of CH3OH and D-atom spectrum of CH3OD have bimodal distributions. O-H (CH3O +H(D)) and C-H (CH2OH(D) +H) dissociations contribute to the fast component. The slow component corresponds to CH2O +H +H(D) production, mainly from three-body photodissociation, plus small contributions from secondary dissociation of CH3O and CH2OH(D). The CH2O +H +H formation is the major photodissociation pathway, with a branching ratio of (CH2O +H +H):(CH3O +H):(CH2OH +H):approximate to 1:0.25:0.15. (C) 2014 Elsevier B.V. All rights reserved.