Background: Factor XII (Hageman Factor) is the initiating factor for the Intrinsic Pathway of Coagulation. Very low levels of Factor XII have been associated with increased levels of activated Partial Thromboplastin Time (aPTT). Association of Factor XII deficiency is more with thromboembolic disorders rather than bleeding tendencies. Aim: To learn more about the relationship of factor XII (Hageman Factor) deficiency and high levels of activated Partial Thromboplastin Time. Case Presentation: The Patient was admitted with complains of recurrent headaches and loin pain. Patient was incidentally found to have prolonged activated Partial Thromboplastin Time. This led to investigations which ultimately provided the evidence of severely low levels of Hageman Factor. Conclusion: Hageman Factor deficiency causes prolonged activated Partial Thromboplastin Time. However, most of the patients are asymptomatic for many years despite Hageman Factor deficiency.