The present study has been carried out in order to evaluate the role of tumor markers in the presurgical assessment of patients with bronchial carcinoma. The carcinoembryonic antigen (CEA), the neuron specific enolase (NSE), the tissue polypeptide antigen (TPA), the carbohydrate antigen 19-9 (CA 19-9) and the carbohydrate antigen 50 (CA 50) have been preoperatively measured in 133 subjects with potentially resectable lung cancers, and in 75 healthy smokers. Sixty-one patients had squamous cell carcinoma, 55 adenocarcinoma and 17 small cell carcinoma. Lobectomy (or bilobectomy) was performed in 74 cases, pneumonectomy in 36 cases, exploratory thoracotomy in 15 cases and a palliative resection in 8 cases. When individual markers were considered, TPA showed the highest sensitivity (85%) and CA 19-9 the lowest sensitivity (11%). Specificity was uniformly superior to 90%. When marker associations were considered, the combined measurement of TPA and NSE gave the best results: both the sensitivity and specificity rates approached 90%. The application of the TPA-NSE association allowed detection of 94% of small cell carcinomas, 89% of adenocarcinomas and 85% of squamous cell carcinomas. A positive correlation was found between the complete resectability of lung cancer and serum levels of CEA, CA 50 and CA 19-9. By using the discriminant analysis, a statistical model yielding identification of about 74% of patients with tumors which were judged potentially resectable according to the pre-operative non-invasive diagnostic procedures and were found to be unresectable at thoracotomy, has been get available.