Multiple hereditary exostosis (MHE) is a rare condition that tends to be overlooked because of its benign nature. The formation of pseudoaneurysm is a rare complication in association with osteochondromatosis. An 8-year-child with MHE presented with a mass behind her left thigh. Imaging confirmed pseudoaneurysm of the popliteal artery. The patient was operated for closure of rent in the arterial wall with a polytetrafluroethylene graft and excision of osteochondroma. At 2 years of follow-up, circulation was normal and the patient was symptom free, without any growth disturbance. This case report highlights the rare possibility of pseudoaneurysm with osteochondroma and focuses on thorough evaluation and proper management of these patients.