This paper describes an investigation of accidents associated with fatal and nonfatal roof-rib falls. Mine Safety and Health Administration accident statistics for U.S. mines during the period 1980-85 were sorted, normalized, and graphed using a computer software program. The statistics indicated that roof and rib accidents have declined 22 pct in the 6-year study period. Moreover, they indicated that there have been increases and/or patterns of roof and rib accidents associated with specific mine characteristics such as mine size, seam height, geographic location, and seasonal variations. Also examined was the worker activity at the time of the roof and/or rib fall accident. The economic effects of roof and rib accidents were emphasized by using a computer program to approximate accident costs. The program estimated that the cost per accident of roof and rib accidents is three times the cost of any other type of underground coal accident.