Atherothrombotic complications are the main cause of mortality in subjects with diabetes. Premature atherosclerosis, increased platelet reactivity and activation of coagulation factors with associated hypofibrinolysis all contribute to increased cardiovascular risk in this population. Blood clot formation represents the last step in the atherothrombotic process, and the structure of the fibrin network has a role in determining predisposition to cardiovascular disease. In this review, we discuss alterations in coagulation factor plasma levels and/or activity in diabetes and clarify their role in predisposition to cardiovascular events. The effect of diabetes on fibrin network structure/fibrinolysis is reviewed and potential mechanisms that modify clot properties are discussed. Finally, modulation of clotting potential by the various therapeutic agents used in diabetes is examined. Understanding the mechanisms by which diabetes influences the coagulation pathway will help to develop more effective treatment strategies to reduce thrombotic events in subjects with this condition.