Many new drugs and drugs in the pipeline are referred to as targeted therapy. Targeted therapies have revolutionized the care of certain cancers, such as chronic myelogenous leukemia, but for other common malignancies, such as colon cancer, the impact on survival has been more modest. These seemingly incremental improvements coupled with the high cost of targeted therapy have focused the debate about the cost of healthcare squarely on oncology. Clinical practice guidelines are a common baseline starting point for this debate. Guidelines reflect clinical evidence and expert judgment, which is necessary to fill in the gaps when clinical evidence is not yet available or is evolving quickly. In addition, clinical guidelines inform other key aspects of oncology care, such as establishing a standard of care, which can then be translated into quality measures. Guidelines can also be reformatted to create an oncology drug compendium or rewritten to provide patient information.