The relation of tumor grade to cancer patient outcome was investigated for 15 anatomic sites using data from the Surveillance, Epidemiology, and End Results Program of the National Cancer Institute, Bethesda, Md. Over 500,000 cases were available for review. In some cases, nine-year follow-up information was also available. The results showed that, stage for stage, the grade further subdivided the overall survival rates for each site into distinct subsets that were significantly different. The study confirms the concept of grade as applied to cancer and the relation of grade to survival. From the results, the conclusions are reached that grading is prognostically valuable, especially when analyzed with respect to survival in a population, and that the grade provides prognostic information in addition to the stage of disease. It is proposed that three grades be adopted to minimize statistical variation. The results are considered significant, since neither standard nor uniform guidelines have existed for grading that pertain to all sites.