Measurements of posterior choroidal artery are made by the method devised by Pachtman et al. 50 cases ofnormal vertebral angiography performed between September, 1974 and July, 1977 at department of Radiology, SeoulNational University hospital are selected and measured. All measurements are expressed as a percentage of thereference length which is in this study the distance between dorsum sellae and the torcula herophili. The distancebetween dorsum sellae and medial choroidal artery as a percentage of reference length is designated as measurementA and that of lateral choroidal artery is measurement B. Measurement C is a percentage of interchoroidal distanceto the reference length. Normal value of measurement A is 47.8%+3.43, B 56.0%+3.83 and C 8.2%+2.62 Discussion onchanges in pathologic state is added.