Samples of seawater, sediment, and the following invertebrates were collected from the Mediterranean Sea in the neighborhood of Alexandria, Egypt: sea urchins (Echinusspp.), clams (Tapesspp.), and wedge shells (Donax trunculus). A total of 165 samples were collected from November 1979 to July 1980. Average counts (per 100 mL or 100 g) ofVibrio parahaemolyticuscontent were as follows: seawater, 36; sea urchins, 349; sediment, 436; wedge shells, 534; clams, 1872. Samples collected in the summer months contained higher levels ofV.parahaemolyticusthan winter samples.