Primary leiomyosarcomas are rare tumors of the lungs. No typical roentgenographic findings of unusual complex of symptoms distinguish this tumor. The most common therapy is surgical resection. Prognosis and significant survivorship are related to the size, grade, metastasis of the lesion. A 25-year-old female patient with chest pain and cough was admitted. In chest X-ray and CT scan, there was a pulmonary nodule in left upper lung field, She was taken a percutaneous needle aspiration biopsy. The result was a spindle cell tumor. Left upper lobe lobectomy was done, and pathologic diagnosis was a low grade leiomyosarcoma arising from left bronchus. During 5 years of follow-up period, she has not shown any metastasis or local recurrence.