Despite a common misconception, bronchogenic carcinoma of the left upper lobe frequently metastasizes to lymph nodes not only in the anterior mediastinum (para-aortic and subaortic) but also in the superior mediastinum. Anterior (parasternal) mediastinotomy can be used to assess only the former compartment. This procedure alone, if not done in conjunction with standard cervical mediastinoscopy, will fail to disclose technically unresectable N2 or N3 disease of the left upper lobe involving the superior mediastinum. We have developed a technique to explore and sample nodes from both regions by extending a standard cervical mediastinoscopy, eliminating the need for a second incision when the anterior mediastinal compartment requires assessment. We have prospectively analyzed the first 100 procedures that we performed. This technique has been found to be accurate and exceptionally safe with one superficial wound infection as the only complication. We can recommend this single staging procedure for preoperative assessment of bronchogenic carcinomas of the left upper lobe.