The authors have studied in 212 patients the diagnostic value of radio-active fibrinogen and rheography in deep venous thrombosis of the leg by comparing the results from these two methods with phlebography. Radio-active fibrinogen seems the better means of diagnosis in early distal phlebitis. However, the method is expansive, the radio-active substance can only be manipulated in certain specialized centers, and is useless in the presence of hematoma. Rheography is less expansive, more easily manipulated, yet less sensitive as only proximal phlebitis can be detected-especially when completely occlusive. In addition, active patient cooperation is necessary. The time needed to realize the two methods is a major obstacle; however, they can be fruitful if integrated into a specialized department for the diagnosis and treatment of thrombo embolic disease.