A number of studies have been done on the tolerance of fish to salt, but there is little information on the effect of salt on growth of fish. In the present study, repeated trials in tanks indicated that selected concentrations of salt have a significant effect on the growth of channel catfish. Subsequent trials in ponds showed a similar effect. The increased growth resulting from selected concentrations of salt is of such magnitude as to be of practical significance in some situations. An explanation for this effect is postulated.