A reanalysis of pertinent data on survival, natural mortality rates and rates of exploitation for largemouth black bass (Micropterus salmoides) is made. It is demonstrated mathematically that a size limit effective one year after the minimum size at which capture is practicable will eventually assure a greater number of large fish in the catch than is possible without a size limit under the conditions observed to date. Large fish are defined as those which are three years or more older than fish at the limiting size for capture.