Radionuclide venography (RNV) is an easily performed, rapid and non-invasive diagnostic examination for the detection of deep-vein thrombosis. Provided the procedure is followed out in a standardized order, the results are highly reliable and accurate, especially in the iliac and femoral veins. Therefore, because of this advantage and the possibility of simultaneous lung perfusion scanning and the lack of serious complications this method fills a gap between contrast phlebography and fibrinogen test. 122 limbs of 69 patients were investigated by RNS. 65% showed pathologic results. In 48% thrombotic venous occlusions could be demonstrated. Pulmonary embolic perfusion defects were found in 46% of patients presenting deep vein thrombosis but only in 15% of patients without pathologic findings in RNV. In correlation with contrast phlebography in 11 patients there was no discrepancy neither in recognition nor in localization of the thrombotic occlusion. The essential findings in RNV and the resulting diagnostic conclusions are demonstrated.