Intensity-modulated radiation therapy (IMRT) is an advanced form of radiotherapy for the treatment of cancer that allows, on one hand, to administer a more homogeneous dose to the patients on the volume to irradiate (which would increase the local control of the disease), and on the other hand, to diminish the toxicity in the organs at risk. This type of treatment is based on imaging techniques, on computer dosimetry programs, and on more precise immobilization accessories. Before delivering IMRT it is necessary to establish a protocol that includes the different phases of the treatment process, that is, the obtaining of anatomical data, beam definition, calculation, dose distribution, and treatment performance and control. In this article we present the basic standards for the IMRT treatment for prostate and head-neck cancer agreed upon a consensus meeting. The follow-up of the recommendations settled down in this document will help in the establishment of a standardized clinical practice -assuring the quality- and a better evaluation of the results of the clinical intervention.