Experience accumulated over several decades in the treatment of head and neck tumors by irradiation has demonstrated the need for a high tumor dose to achieve local control. With external beam irradiation alone, it is difficult to spare adjacent normal tissues, resulting in undesirable late effects on the salivary glands, mandible, and muscles of mastication. Interstitial implantation is ideally suited to deliver a high dose limited to the volume of the primary tumor, thus maximizing tumor control while minimizing complications. A large experience has been accumulated with low dose rate (LDR) brachytherapy in treatment of carcinoma of oral cavity, oropharynx, and nasopharynx. Recent analysis of large clinical series provided data indicating that modalities of LDR brachytherapy should be optimized in treating these tumors for increasing therapeutic ratio. LDR brachytherapy is now challenged by high dose rate (HDR) brachytherapy and pulsed dose rate (PDR) brachytherapy. Preliminary results obtained with these 2 last modalities will be discussed. Copyright 2002 by W.B. Saunders Company