Karyotypes from 13 spp. of the North American cyprinid genus Notropis: N. chrysocephalus, N. fumeus, N. longirostris, N. lutrensis, N. oxyrhynchus, N. roseipinnis, N. sabinae, N. shumardi, N. signipinnis, N. texanus, N. umbratilis, N. venustus and N. volucellus were examined. All 13 spp. have 2n = 50 chromosomes. Estimated haploid arm numbers among the 13 spp. ranged from 46-50. One-armed chromosomes (centromeres subterminal to terminal) comprised only a small portion of the karyotype of each species. Chromosomal evolution in Notropis, and in North American Cyprinidae, has been remarkably conservative. Almost all species karyotyped have 2n = 50 chromosomes, and with one e..ception, cyprinid species with 50 chromosomes vary in estimated haploid chromosome arm number from only 46-50. Speciation in these fishes may have been rapid. Gross chromosomal rearrangement has probably played only a very minor role in the speciation and evolution of these fish.