The coagulation system, which is activated in most cancer patients, has an important role in tumour biology. It may make a substantial contribution to tumour angiogenesis, which represents an imbalance in the normal mechanisms that allow organised healing after injury. The recently recognised, but steadily growing, knowledge of the relationship between the coagulation and angiogenesis pathways has research and clinical implications. Manipulation of these systems may minimise both the neoangiogenesis essential for tumour growth and associated thromboembolic complications. However, since surgery is the primary treatment for most cancers, the angiogenesis of wound healing and haemostatic competence must be maintained. In this article, we summarise the complex interactions between the coagulation system and the angiogenic process that occur in cancer growth. We focus upon the contributions of the vascular endothelium, platelets, and coagulation factors to the angiogenic process and explore the coagulation system as a therapeutic target.