Treatment options for unresectable pancreatic cancer, including concurrent chemoradiotherapy, chemotherapy alone, and chemotherapy followed by chemoradiotherapy, are largely ineffective and result in a median survival of approximately 10-12 months. Although quality data on the benefit of radiotherapy in unresectable pancreatic cancer are lacking, it seems unlikely that the low-efficacy chemotherapy used for pancreatic cancer would control gross disease. Current regimens deliver low, ineffective doses of radiation and are associated with high rates of local failure. New technological advances, such as intensity-modulated radiotherapy, now allow the safe delivery of high-dose, highly conformal radiotherapy concurrently with full systemic doses of chemotherapy. We review new knowledge related to pattern of failure, target definition, and target motion and discuss the implications of these data on modern radiotherapy treatment planning and delivery. While it is clear that breakthroughs in treatment would come mostly from advances in systemic therapy, the evidence suggests that radiotherapy should not fall out of use, but rather be intensified.