We use extreme-value theory to estimate the ultimate world records for the 100-m running, for both men and women. For this aim we collected the fastest personal best times set between January 1991 and June 2008. Estimators of the extreme-value index are based on a certain number of upper order statistics. To optimize this number of order statistics we minimize the asymptotic mean-squared error of the moment estimator. Using the thus obtained estimate for the extreme-value index, the right endpoint of the speed distribution is estimated. The corresponding time can be interpreted as the estimated ultimate world record: the best possible time that could be run in the near future. We find 9.51 seconds for the 100-m men and 10.33 seconds for the women.