The Tampa Bay Estuary Program and its partners have identified the protection of uncontaminated sediments in Tampa Bay and the reduction in the level of contamination of contaminated sediments as important, broad goals for the Comprehensive Conservation and Management of the bays environment (TBNEP CCMP, 1996). The TBEP has been working for more than six years to develop an empirically based, objective process for establishing specific sediment quality targets to meet these broad goals. Recently, the TBEP work to develop sediment quality targets has focused on quantifying empirical relationships between observed responses in benthic organisms and measured levels of sediment contamination. The benthic organism responses included incidence of acute toxicity, chronic toxicity, and benthic community impairment (Shannon-Weiner Diversity Index). The results of this work were reported recently in MacDonald et al., In Review, and they were discussed in depth at a March 5, 2002 TBEP Sediment Quality Target Workshop. Among other interests, the participants of the March 5 workshop expressed an interest in reviewing the relative contributions of physical parameters such as sediment grain size and salinity to explaining the distribution of benthic organisms. The purpose of this technical memorandum is to support the ongoing target setting process by providing a review of the observed relative contributions of physical parameters to the explanation of benthic organism distributions, and to present recent relevant observations from the ongoing Tampa Bay Benthic Program. The specific objectives of this technical memorandum are: to present recent relevant observations from the Tampa Bay Benthic Program, and to estimate the relative importance of salinity and sediment size in determining benthic health in Tampa Bay.