A systematic review and evaluation of evidence for photodynamic therapy in nonsmall cell lung cancer was undertaken. Two authors selected relevant articles according to predefined criteria. External feedback was obtained from Ontario clinicians and the provincial Lung Cancer Disease Site Group approved the review. The Group concluded that photodynamic therapy may have a role in treating superficial early stage disease or in palliating symptoms in late stage disease. The safety and effectiveness of photodynamic therapy compared with other treatment modalities remains undefined. Serious adverse effects can occur; therefore, the suitability of patients for this treatment should be carefully assessed.