In Raynauds phenomenon, the authors measured finger blood flow after ice water exposure by analyzing the time activity curve of radionuclide angiography on both hands. The results were as follows: 1) The digital blood fiow did not decrease after ice water exposure in normal subjects. 2) Jn the patients with Raynauds phenomenon, there were two groups: the one had decreased digital blood flow after cold exposure, and the other had paradoxically increased digital blood flow after cold exposure. 3) There was no dlfference in the digital blood fiow of hand in room temperature between the normal and the patients with reduced digital blood flow after cold exposure, but the digital blood flow af the hand in room temperaure was markedly reduced in the patients with paradoxically increased flow after cold exposure. 4) In the static image the difference was not significant in comparision with the dynamic study, because it represents pooling of the blood in the vein rather than flow. 5) After the treatment with nifedipine, the digital blood flow increased. In conclusion, the radionuclide angiography was useful in measuring the digital blood flow in Raynauds phenomenon, and further st#udies with various drugs is expected.