Cutter roof failure is a ground control problem that exposes miners to the danger of falling roof rock and frequently results in massive roof failures, causing delays in production, increased mining costs, and loss of recoverable reserves. It occurs most often in the northern Appalachian coalfields, but it also occurs in each of the major coal basins where underground mining is practiced. Cutter roof is unpredictable, creating widely variable problems. The uniqueness of this problem has limited the techniques available for its treatment. Trial and error has proven unsatisfactory in many cases, as the causes often differ from mine to mine; thus the selection of the optimum control technique has proven to be a difficult task. This U.S. Bureau of Mines article presents information on the causes of cutter roof failure and the effective control techniques.