Advances in treatment delivery of external beam radiotherapy (EBRT) have facilitated improvement in treatment efficacy of radiotherapy (RT) for prostate cancer by enabling safe dose escalation. Intensity-modulated radiation therapy (IMRT) has become a standard current form of treatment delivery. Various protocols for fractionation exist, and EBRT is used in both the definitive and postoperative settings. However, all approaches rely on accurate target delineation, treatment planning, and patient setup. This chapter will describe the approach that is employed at Memorial Sloan Kettering Cancer Center (MSKCC).