The use of bioremediation as a supplemental cleanup technology in the Exxon Valdez oil spill, in Prince William Sound, Alaska, has proven to be a good example of the problems and successes associated with the practical application in this technology. Field studies conducted by scientists from the U.S. Environmental Protection Agency have demonstrated that oil degradation by indigenous microflora on the beaches of Prince William Sound could be significantly accelerated by adding fertilizer directly to the surfaces of oil-contaminated beaches. The results from the application of an oleophilic fertilizer are presented as exemplary field and laboratory information. The fertilizer enhanced biodegradation of the oil, as measured by changes in oil composition and bulk oil weight per unit of beach material, by approximately twofold relative to untreated controls. These studies supported bioremediation as a useful cleanup alternative that was subsequently used by Exxon on a large scale. They have also generated a number of insightful lessons that have significant relevance to future oil bioremediation efforts. This chapter discusses these lessons and examines complications and difficulties in assessing the effectiveness of bioremediation in the field.