Extra-intestinal manifestations of Inflammatory Bowel Disease occur in 25% of cases. Vascular manifestations are rare and occur in 1 to 8% of cases. The most relevant are Deep Venous Thrombosis (DVT) and Pulmonary Embolism (PE). They both represent an important cause of morbidity and mortality and increase the risk of DVT recurrence. These are the reasons why prevention and early recognition of these entities are important. There is no agreement yet about the prophylaxis of DVT, neither primary nor secondary, to prevent recurrences in this group of patients. We report the case of a 52 year-old male patient who was admitted due to DVT in the left leg and who was simultaneously diagnosed with Ulcerative Colitis (Truelove activity index:16 points) during this same hospitalization. Doppler ultrasonography of the leg showed a thrombus in the left popliteal vein. Colonoscopy showed nodules, erosions, edema and erythema in the whole colonic mucosa in a continuous fashion. The patient was treated with Sulfazalasine 2gr per day, resulting in total remission of the intestinal complaints, and with Enoxaparin 1.5 IU/Kg per day followed by warfarin 5 mg per day, resulting in disappearance of the popliteal thrombus at 4 weeks. Oral anticoagulant treatment continued for 6 months and no DVT recurrences were seen during follow-up appointments.