Osteochondromas (exostoses) are the most common benign bone tumours. In most cases, osteochondroma occurs as a solitary lesion. Hereditary multiple osteochondromatosis is an autosomal dominant disorder manifested by multiple exostoses most commonly located at the metaphyses of long bones, the iliac crest, the ribs, the vertebral borders, and scapulas. Vascular complications of multiple osteochondromatosis are very rare, most frequently affecting the popliteal artery. The authors report the case of a 27-year-old female patient with hereditary multiple osteochondromatosis that was complicated by femoropopliteal deep vein thrombosis and giant popliteal artery pseudoaneurysm.