The results of 150 placental scans are reported, using 99mTc erythrocytes, 113mIn gelatine and 113mIn tranferrin. Accuracy was checked at surgery and compared with ultra sound findings. In 62% of patients, the indications for placental scintigraphy was suspicion of placenta praevia because of bleeding in late pregnancy. In 38% placental localisation was performed for amniocentesis for Rh incompatibility. Localisation of the placenta was accomplished in 98.6% by scanning and in 95% by ultra sound. Accuracy of scanning was 94% and ultra sound 70%. Placental scanning is at present the most accurate method for a placental localisation and should therefore be used when an accurate diagnosis cannot be achieved by other techniques.