Five patients had a solitary fibrous tumor of the pleura; a well-known but rare entity. In all cases, biopsy by a transthoracic cutting needle (Tru-Cut; Travenol; Deerfield, IL) yielded specimens adequate for histologic analysis and gave the clue to the diagnosis. In four patients, surgical resection confirmed the diagnosis. The opportunity for and interest in diagnosing these tumors by transthoracic cutting needle biopsy before surgery are discussed. An accurate diagnosis of solitary fibrous tumors of the pleura can be made by a minimally invasive procedure; this allows for a more informed allocation of surgical resources.