Temperature effects on the hatching success of eggs of the white bass (Morone chrysops) were determined by exposing sample lots of recently fertilized eggs to 10 constant temperatures, 6 through 30C. Different lots of eggs were exposed to test temperatures before gastrulation, and after closure of the blastopore in the embryo. The percentages of normal larvae hatched were not significantly (P > 0.05) impaired in eggs exposed before gastrulation at temperatures from 18 through 26C, nor in those first exposed after closure of the blastopore at temperatures from 14 through 26C. Eggs incubated in 14C hatched 4.5 days after fertilization, and those incubated at 26C required only 1 day. The 24-h TL50 for white bass larvae exposed within 24 h of hatching and acclimated to 14, 18, 20 and 26C was between 30 and 32C, and was not altered by the acclimation temperatures tested.