We conducted a study of 19 patients who had laryngeal cancer with subglottic extension (LCSE) and pathologically negative lymph nodes (pN0) following total laryngectomy and neck dissection (TLND). These patients had undergone surgery during a 17-year period from 1986 through 2002. Of this group, 9 did not receive postoperative radiotherapy (non-RT group) and 10 did (RT group). Adjuvant irradiation had been administered to those with additional histopathologic risk factors for recurrence. We found that recurrence rates in the neck were 44% in the non-RT group and 11% in the RT group (1 of 9 evaluable patients), and the corresponding 5-year disease-free survival rates were 51 and 89%. While both of these differences were clinically significant, neither was statistically significant (p = 0.29 and p = 0.14, respectively). The presence of LCSE was not known prior to or during TLND in 4 non-RT patients and in 7 RT patients; their corresponding neck recurrence rates were 50 and 0%. Two of 8 patients (25%) whose ipsilateral lobe of the thyroid gland was not removed experienced a stomal recurrence. We conclude that three factors can be used to identify patients with pN0 LCSE who may be candidates for adjuvant postoperative radiotherapy: (1) a failure to remove the ipsilateral thyroid gland lobe during TLND, (2) a failure to examine the level VI lymph node for metastatic disease status, and (3) unfavorable histopathologic findings.