The purpose of this paper is to compare various indicators of microbiological contamination in coastal areas near estuaries around the world. A major factor contributing to the presence of fecal coliforms is the geomorphology of the area, and, more particularly, whether the area concerned is an open or enclosed bay, the climate of the area, its tourism development, and, lastly, the urban, agricultural, livestock, or industrial activities carried out near river mouths. The aim was also to attempt to systematize the microbiological contamination of the above – mentioned estuaries around the world for broader applicability. The method used and the experimental apparatus for the isolation of bacteria was the membrane filtration method described in ISO 7704:1985. For the growth and enumeration of total coliforms and Escherichia coli the method described in ISO 9308-1 was used, while for enterococcus the one described in ISO 7899-2:2001. No statistically significant difference was found at many points in Greece and Spain, for either of the two patho-genic bacteria. In this work, the documentation of the microbiological contamination of river del-tas was achieved in similar areas (Greece and Spain) and could be applicable throughout the Mediterranean.