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The survival and reproduction of Lumbricus terrestris Linne (Red Wiggler) and Eudrilus eugeniae Grinsburg, 1866 (African Giant) earthworms were followed in Everglades muck and Arredondo loamy fine sand treated with 11 herbicides at five rates. Generally, E. eugeniae were more susceptible to the herbicides than L. terrestris and both suffered greater damage in Arredondo fine sand than in Everglades muck. Eggs and young were found in all treatments in the muck while none were observed in the fine sand. Several of the compounds had no effect, even at 64 ppm. Apart from dalapon, which had a significant effect on E. eugeniae at 8 ppm, the other compounds were ineffective below 16 ppm in Arredondo fine sand, and 32 ppm in Everglades muck. These levels are much in excess of the recommended rates for field applications. Rotifers appear under moist conditions in most soils, and their diet includes soil algae. In solution culture, no direct toxic effects could be attributed to any one of the seven herbicides tested, but significant reductions in numbers of rotifers resulted from treatments which adversely affected the growth of unicellular algae. This demonstrated the indirect effect which some herbicides may have on an organism by way of a given food chain.