We retrospectively identified 73 patients who underwent percutaneous core-needle lung biopsy under CT scan fluoroscopic guidance for pulmonary lesions measuring ≤10 mm between October 2002 and June 2009. The biopsy specimen results as well as the final diagnoses were available in 50 of these patients, and the results were compared (one lesion per patient). The diagnostic performance was also compared according to the lesion size (≤8 mm [n =22] vs >8 mm [n =28]), the depth from the lung surface (≤25 mm [n =32] vs >25 mm [n =18]), and the length of the needle path (≤7 cm [n =35] vs >7 cm [n =15]). Finally, all 73 cases were reviewed for complications. The patients’ age, gender, lesion size, depth from the lung surface, and length of the needle path were as follows, respectively (range in parentheses): 62±12 years of age (34-81), 31 men and 36 women, 8.6±1.5 mm (4-10), 23±16 mm (0-76), and 64±21 mm (33-125). The overall sensitivity, specificity, and accuracy were 90%, 100%, and 94%, respectively (Table 1). The sensitivity and accuracy (Fisher exact test) were not significantly affected by the size of the lesions (≤8 mm, 91% and 95%; 9-10 mm, 89% and 93%; P=.86 and P=.70, respectively). The diagnostic sensitivity and accuracy were lower in the lesions deeper from the lung surface (0-25 mm, 100% and 100%; >25 mm, 79% and 83%; P=.06 and P=.017, respectively) and in lesions with the longer needle path (≤7 cm, 100% and 100%; >7 cm, 70% and 80%; P=.012 and P=.006, respectively). Eight patients (11%) developed pneumothoraces. One patient required manual aspiration, but the others resolved conservatively. Four patients (6%) experienced mild hemoptysis, which resolved conservatively for all of them. As of this report, there have been no suspected cases of needle tract disseminations.