Fecundity of the spotted seatrout, Cynoscion nebulosus, from Louisiana waters was estimated by the gravimetric method. By actual counts this method involved an error of 6.93 percent. Fecundity increased with length and age. The ovary is heavier than the testis for individuals (greater than 280 millimeters in total length) of comparable age and size. Mean volume, mean diameter of ova, mean number of eggs per gram weight of ovary, and mean testis weight indicate a spawning peak in July. Members of age-groups II, III, and IV contribute 91.9 percent of the supply of eggs. Members of age-group I contribute little to the supply of eggs.