Microarthropod population diversity, distribution, and species composition were studied in three South Carolina old fields with the use of fiberglass—mesh litterbags. Mean total arthropod densities were highest in a 1st—year successional field (abandoned cornfield), lowest in a 12—year broomsedge field, and intermediate in a 12—year lespedeza field. Densities differed significantly with season, field, and litter type within field. Litter moisture content also differed significantly with these factors and changes in moisture were correlated with changes in density or microarthropods. Both species diversity and species composition differed significantly between fields, but litter type had no significant effect. Conclusions were (1) the litter fauna is a transient subset of a larger and possibly more diverse soil fauna, present in the litter only during favorable moisture regimes; (2) species diversity and composition of the litter fauna are determined primarily by the successional stage of the field and are affected little by the introduction of allochthonous litter in the small amounts contained in the decimeter—square litterbags used in this study.