The purpose of this study was to compare the differences in abundance of Nematoda, Gastrotricha, and Harpacticoida between depths in the sediment at various tide levels and between depths at various sites with increasing time of exposure. It also examines the relationship between the abundances of meiofaunal groups and the mean grain size of the sediment. This study was also a part of the continual baseline-data gathering program for the South Slough Estuarine Sanctuary, Delane A. Munson, Manager.