A case of benign paraganglioma arising in the middle mediastinum was reported. 201Tl SPECT showed high accumulation in tumor on early images at 15 min and reduced on late images at 3 hours after infusion. The patient was a 57 year old female. In the contrast enhanced CT, 3 x 4 cm tumor with intensive enhancement was recognized at the right middle mediastinum. Under the radiological images, the tumor was surgically removed. The pathologic diagnosis was a low atypical nonfunctioning aortico-pulmonary paraganglioma. This report was suggested that 201Tl SPECT was useful for differential diagnosis of benign neurogenic mediastinal neoplasms.