The effects of grid system mosquito control ditching on salt marsh phanerogams, salt marsh snails (Melampus bidentatus), and two species of fiddler crabs (Uca minax and Uca pugnax) were investigated over a two-year period (1973-1974) in Kent and Sussex Countries, Delaware. Reports of research conducted from 1936 to 1946 on one of the present study areas had indicated that ditching caused deleterious changes in the plant community structure. However, channel dredging in the nearby Mispillion river in 1933 and 1935 may have had an appreciable influence on the plant succession reported in these earlier studies. Vegetational cover typing of the area shows that the 1974 plant community structure is similar to what it was prior to ditching in 1936. Random quadrat sampling showed the densities of Uca and Melampus to be significantly greater (P<0.05) on a ditched marsh as compared to an adjacent unditched marsh.