To determine the efficacy of re-irradiation of patients with head and neck carcinoma we reviewed the pertinent literature. Depending on the location and extent of the tumor, re-irradiation may be accomplished with external beam radiotherapy (RT), brachytherapy, intraoperative RT, and/or radiosurgery. The likelihood of cure is impacted by the interval between the initial course of RT and re-irradiation, whether the carcinoma is a recurrence or a second primary tumor, initial T-stage, and recurrent T-stage (rT-stage), whether the gross disease is isolated or local-regional, and histology. Patients with T1-T2 N0 second primary tumors have a relatively high likelihood of cure, whereas those with recurrent T3-T4 cancers, a short disease-free interval, and/or associated with a regional recurrence have a very low probability of cure. The likelihood of severe late complications is relatively high and is related to prior RT dose, primary site, retreatment RT dose, treatment volume, and technique. Previously irradiated patients with T1-T2 N0 carcinomas who are not surgical candidates may benefit from re-irradiation, albeit with an elevated risk of late complications. Those with advanced recurrences are unlikely to benefit from re-irradiation and should be considered for either a prospective clinical trial or for palliative chemotherapy or supportive care.