A database for overruns of runways by aircraft is described. It contains 185 fields of data on 180 accidents and incidents that occurred in the English-speaking world between 1980 and 1998 to jet and turboprop aircraft used for transporting passengers or freight on civil operations. The data have been normalized to account for differences in airfield characteristics and aircraft performance. A first-cut analysis shows about two overruns per 10 million movements, three-quarters being after landing and one-quarter after an aborted takeoff. The majority of takeoff overruns occurred after a late decision to abort. A high proportion of overruns involves aircraft operating near or over their legal operating weight. Wet runways, contaminated runways, and tailwinds were factors in many overruns, particularly after landing fast or long. There is no statistical evidence that a precision approach improves the quality of approaches that subsequently become overruns. A large number of overruns have terminated beyond the previous international recommendations for the length of protection off the end of runways, and some 10% exceed the new recommendations.