Nutrient loading has been implicated as a major cause of ecological changes in Everglades wetlands. The response of soil microbial properties to eutrophication was assessed for four wetlands in the Everglades: Water Conservation Area (WCA)-1, WCA-2a, WCA-3a, and Taylor Slough of Everglades National Park. Impacts of nutrient loading were most evident by the development of gradients in soil total P from peripheral to interior areas of wetlands following paths of surface water flow. Total P averaged 185% and 140% greater for impacted than oligotrophic areas for floc and soil (0-3 cm), respectively. Microbial biomass C and N exhibited a mixed response to nutrient enrichment. In contrast, microbial biomass P averaged 97% and 52% higher at impacted than oligotrophic areas for floc and soil, respectively. Floc was more responsive to eutrophication than underlying soil, while heterotrophic microbial activity was generally not indicative of nutrient enrichment. The sensitive indicators of nutrient enrichment were total P, microbial biomass P, and mineralized P. Mineralized P was the most sensitive indicator of nutrient enrichment, being 689% and 135% higher at impacted than oligotrophic areas for floc and soil, respectively. Microbial indicators in the southern wetlands, WCA-3a and Taylor Slough, were most responsive to nutrient loading than northern wetlands receiving higher P loads. Delineation of impacted and oligotrophic areas in Everglades wetlands may serve as a baseline to assess future impacts of eutrophication. Continued nutrient loading into oligotrophic areas of wetlands may enhance heterotrophic microbial activity and stimulate organic matter decomposition and nutrient regeneration, and further alter the Everglades ecosystem.