Fracture of the clavicle is a common injury, accounting for 5–12% of all fractures and up to 44% of injuries of the shoulder girdle. About 70–80% of these fractures are in the middle third of the clavicle. Damage to neurovascular structures associated with closed fractures of the clavicle due to blunt trauma is rare and more frequently related to penetrating injuries. The usual mechanisms of injury include fall on an outstretched hand or on the point of the shoulder and direct or indirect trauma associated with contact sports. Literature about the incidence of deep venous thrombosis in upper limbs in orthopedic practice is limited [3]. This case report presents a case of upper-extremity deep venous thrombosis following conservative treatment of an acute clavicular fracture. A 50-year-old female was presented with a fractured left clavicle after a high-velocity motorcycle accident. At presentation, there were no associated injuries and she was intact neurovascularly. X-ray showed a middle third left clavicle fracture which was treated conservatively in a sling. After 17 days of injury, the patient was again presented with acute discomfort and swelling of the left upper extremity. The patient had no risk factors for venous thromboembolism. However, a deep venous thrombosis was clinically suspected. Doppler ultrasonography confirmed thrombotic occlusion of both axillary and basilic veins. Anticoagulation therapy was initiated and continued for a total of three months. At three months follow-up, the fracture healed successfully and the swelling completely subsided. We conclude that a high index of suspicion is necessary to rule out possible vascular lesions in cases of high-energy blunt trauma to the shoulder associated with clavicular fracture. Treating it would prevent a potentially fatal pulmonary embolism.