Evolution. In the article “Genetic evidence for a Paleolithic human population expansion in Africa” by David E. Reich and David B. Goldstein, which appeared in number 14, July 7, 1998, of Proc. Natl. Acad. Sci. USA (95, 8119–8123), the following correction should be noted. In our article about human population expansions, we made some inferences about a detected expansion in Africa, and for this purpose we used an estimated mutation rate for human dinucleotide microsatellites that is slightly different from the one reported in ref. 13. If we perform the calculations again with the referenced mutation rate of 5.6 × 10⁻⁴ per generation, the allowed dates for expansion are 44,000–570,000 years ago (instead of 49,000–640,000 years), and the peaks of the likelihood surface are 132,000 and 325,000 years ago (instead of 148,000 and 364,000 years). In addition, the maximum pre-expansion effective population size is 5,900 (instead of 6,600), the minimum post-expansion effective population size is 7,500 (instead of 8,400), and the maximum effective population size during the narrowest point of the hypothetical bottleneck is 6,200 (instead of 6,900). These are the only numerical changes in the paper. Our conclusions are not affected by these changes.