The authors present a retrospective analysis of 138 patients with squamous cell carcinoma of the hypopharynx and larynx treated with post-operative irradiation. Overall tumoral control rate within the treated areas was 73.9%, uncorrected actuarial survival rates at 3 years and at 5 years were respectively 49.4 and 37.6%. The clinical status (TNM-UICC, 4th edition, 1987) seems to be the main determinant for the prognosis in terms of cervical tumoral control. Patients with N0-N1 nodal stage presented 14/88 (15.9%) cervical failures, while patients staged as N2-N3 presented 22/50 (44%) tumoral recurrences within the treated areas (P less than 0.001). Pyriform sinus tumors were found to present cervical relapses in 13/32 cases (40.6%). This recurrence rate was significantly higher than cervical failure risk in other tumoral sites (P less than 0.05). Cervical relapse (P less than 0.0001), N2-N3 nodal stage and pyriform sinus localization (P less than 0.05) were all found to increase metastasis rate. On the other hand, our results show that the use of post-operative irradiation reduces the prognostic influence of the primary tumor volume; in the same manner, the use of modulated post-operative external irradiation permits the control of microscopically positive surgical margins. In conclusion, the initial staging alone is sufficient to safely evaluate the risk of cervical relapse or metastatic spread; the use of these clinical parameters for selecting patients who could benefit from adjunctive chemotherapy is discussed.