Radiotherapy planning studies have confirmed dosimetric advantages of intensity-modulated radiation therapy over conventional and conformal radiation therapy. Utilization of intensity-modulated radiation therapy is ideal in head and neck cancer patients. Critical structures can be spared due to sharp dose gradients and limited organ motion with correct immobilization. Initial clinical results have shown excellent locoregional control, in part due to the delivery of high doses to the target volume. Reductions in acute toxicities and xerostomia through parotid sparing have been notable benefits. However, long-term outcomes with regards to local control and late toxicities with intensity-modulated radiation therapy are still lacking. This review focuses on the implementation of intensity-modulated radiation therapy for the treatment of head and neck cancers, with a specific focus on set-up uncertainties, dose prescription and target volume determination and delineation.