Results of 133 thoracic percutaneous fine-needle aspiration biopsies performed with a new dual cutting edge needle were analyzed to see if it could reduce the false-negative rate for malignancy compared with that achieved with a sharply beveled spinal needle. Results of cytologic examinations were compared with those of histopathologic examinations. Cores of tissue for histopathology could be obtained in only 51 biopsies (one of which was lost). Sensitivity of cytology (vs. histopathology) was 77.8% (vs. 57.1%); specificity and positive predictive value, 100% (same); and negative predictive value, 64.3% (vs. 46.4%). In 44 of 50 biopsies, cytologic results were equal to or better than histopathologic results diagnostically. In six biopsies (including two cases of hamartoma), the histopathologic result improved upon the cytologic result. There were no biopsies for which cytologic results were negative and histopathologic results were positive for malignancy. Use of this needle did not improve the false-negative rate for malignancy, although it did allow specific diagnosis of a hamartoma in two cases.