Objective: This study was undertaken to determine the recurrence rate after limited resection of small lung carcinoma and to evaluate intraoperative frozen-section examination accuracy for Noguchi classification. Methods: Enrollment requirements were as follows: pulmonary nodule 2 cm or smaller, diagnosed or suspected clinical T1 N0 M0 carcinoma in the lung periphery, and ground-glass opacity findings and lack of evident pleural indentations or vascular convergence on high-resolution computed tomographic scan. A wedge or segmental resection specimen, removed with custom stapler cartridges, was immediately reinflated and examined by frozen-section with hematoxylin-eosin and Victoria blue-van Gieson stains. If the tumor was confirmed as Noguchi type A or B with resection margins greater than 1 cm, the patient was closed and followed up on an outpatient basis. End points were 5-year disease-free survival and intraoperative classification accuracy. Results: From August 1998 through October 2002, a total of 50 patients were enrolled (20 men and 30 women, ages 30-77 years). Tumor sizes ranged from 2 to 21 min (11 mm average). There were 2 Noguchi type A tumors, 23 Noguchi type B turnors, 15 Noguchi type C tumors, 5 atypical adenomatous hyperplasias, 4 fibroses, and 1 granuloma. Frozen-section accuracy was approximately 98% (39/ 40). One intraoperative type B diagnosis was revised to type C after postoperative pathologic study. No morbidity, mortality, or recurrence has been seen with a median follow-up of 50 months. Conclusion: Noguchi type A and B tumors may well be in situ carcinomas, and frozen-section examination was highly accurate. Neither local recurrence nor distant metastases have been found to date. Limited resection initial results appear promising.