Measurements of posterior choroidal artery are made by the method devised by Pachtman et al. 50 cases of normal vertebral angiogrphy performed between September, 1974 and July, 1977 at department of Radiology, Seoul National University Hospital are selected and measured. All measurements are expressed as a percentage of the reference length which is in this study the distance between dorsum sellae and the torcula herophili. The distance between dorsum sellae and medial choroidal artery as a percentage of reference length is designated as measurement A and that of lateral choroidal artery is measurement B. Measurement C is a percentage of interchoroidal distance to the reference length. Normal value of measurement A is 47.8%$pm$3.43, B 56.0%$pm$3.83 and C 8.2%$pm$2.62. Discussion on changes in pathologic state is added.