The quest for an ideal anticoagulant is ongoing. Oral agents that do not require blood level monitoring are presently undergoing taut scrutiny for efficacies and potential side effects, and would potentially soon revolutionize coagulation medicine. The first part of this article reviews oral Factor Xa inhibitors, such as rivaroxaban, apixaban, eribaxaban, edoxaban and YM150--exploring the outcomes of major clinical trials for prophylaxis and treatment of venous thromboembolism--and also briefly outlining their pharmacological properties. The second part of the article (in a separate issue) will cover oral Factor IIa (thrombin), such as dabigatran and AZD0837 and oral Factor IX inhibitors, such as TTP889.