Photodynamic therapy has had a complex 30 year history. There have been significant successes including numerous regulatory agency approvals in the United States and around the world. PDT was for a time the standard of care for a form of macular degeneration, and it is today the only ablative therapy approved by the US FDA for the treatment of Barrett's esophagus with high grade dysplasia. Advances in image guided, minimally invasive intervention have opened up new opportunities to deliver PDT to solid tumors virtually anywhere in the body. Despite these many advances, it must be acknowledged that PDT continues to struggle for more widespread clinical acceptance as a contributor in the ever expanding repertoire of cancer therapies. Commercialization has been agonizingly slow to develop. Nevertheless the fact that PDT offers high efficacy while carrying so little toxicity for the patient creates significant opportunities for novel clinical trials and for exploring new combinationtherapies. The urgency of well chosen translational studies has never been greater.