Until the discovery of activated protein C resistance (APCR), less than 10% of patients with venous thromboembolism (VT) showed defects in proteins involved in the inhibition of coagulation. APCR is caused by a single point mutation in the factor V gene, and it is accepted that APCR is associated with an increased risk for VT. In this work, we studied the prevalence of APCR in venous thromboembolic patients and found it to be 10.5% compared with 4.5% in controls (p = 0.105).