Notropis roseipinnis is a small southern minnow inhabiting small tributary streams in the Gulf Coastal Plain typified by rapidly fluctuating environmental conditions. The reproductive season extends from late March into August or early September in the Jourdan River system, Hancock County, Mississippi. The sex ratio was not different from 1:1 and the mean sizes of males and females were similar. Most fish were mature by about 30 mm standard length (SL). The number of mature ova was correlated with the size of the female, ranging from 50 to 293 for females 29.6-46.6 mm SL. There were significant differences in the number of mature ova with time. Two peaks were indicated, one at the beginning of the reproductive season and one in the latter half. The mean diameter of mature ova (0.65-0.85 mm, mean 0.77) was not significantly correlated with fish length.