Cancer and venous thromboembolism (VTE), VTE and cancer: there is a close bond between these two diseases. On the one hand, a cancer patient runs a high risk of developing VTE. Certain cancer-specific factors, such as its metastatic nature increase this risk. The means involved in the care of cancer (insertion of a venous catheter, chemotherapy, etc.) also increase the probability of a thromboembolism. On the other hand, VTE, especially if it is idiopathic, may be the harbinger of a neoplasm. The present paper involves the dual nature of this relationship, first dealing with several points specific to the occurrence of VTE in a cancer patient, before dealing with the specific care in a curative and prophylactic situation. VTE is then considered as a clinical manifestation prior to a cancer. Several characteristics evoking an underlying neoplasm are known. However, the benefits of the screening for cancer when confronted with an episode of VTE remains to be debated.