Résumé : Treatment of hypernephroma presenting with atria-caval involvement without distant metastases is a surgical challenge. The procedures used in three different cases are described. In one case the caval thrombus extending into the atria-caval junction was delivered during clamping of the atrium without cardiovascular bypass. In another case the remaining atrial thrombus was removed in a second session with cardiovascular bypass. For the third case cardiac bypass was established immediately to permit safe and complete removal of the atria-caval thrombus. In order to plan the surgical procedure adequately, it appears essential to determine exactly the upper level of the thrombus. In cases with atrial involvement, cardiovascular bypass is advisable to perform radical surgery under the safest conditions. © 1984 Springer-Verlag.