The experience with 212 transthoracic fine-needle aspiration biopsy cytology specimens of mass lesions of the lung at a small Canadian hospital is reviewed. The technique showed a sensitivity of 78.0%, a specificity of 85.7%, a positive predictive value of 98.5%, and a negative predictive value of 25.0% when the cytological diagnoses were compared with the final clinicopathological diagnoses listed in the patients' charts. There was only one false positive diagnosis of malignancy. Diagnoses based on cytology of the aspirates were compared with histological diagnoses in 127 cases and the accuracy of typing of the major groups of carcinoma was assessed. Distinction between small-cell carcinoma and non-small-cell carcinoma was usually accurate and fairly good correlation was achieved for all major types of carcinoma. The results for typing of the neoplasm are not as good as those from larger centres in the world. The technique is considered to be useful even in the setting of a small hospital.