SummaryThe distribuition of 51Cr has been studied in mice by whole-body radioautography after a single intravenous injection of 51CrCl3.Hard tissues, skin, liver, cartilage and yolk sack epithelium were the tissues showing the highest concentration of radiochromium. Blood, brain, muscles and the pancreas showed a low uptake of 51Cr. A placental transfer of chromium from the pregnant mother to the fetus was demonstrated. An uptake in the fetal bone and skin was visible.