The Corallinales of the Aegean coasts of Turkey have been relatively little studied, from both the floristic and the ecological point of view. The Turkish coasts offer a wide variety of environmental conditions, and the present study identifies and characterizes not only the presence or absence of these species, but also assesses their value as bioindicators. Qualitative collection of Corallinales was performed at 14 sites in a bathymetric range from 2 to 5 m depth, where, at the same stations, the main environmental variables were recorded. The subsequent data analysis proceeds in the following three-phase procedure: i) identification of well-characterized sample groups with regards to the ecological factors mostly influencing their floristic composition; ii) identification of ecological species groups on the basis of their frequency in the sample groups; iii) ecological gradient analysis based on a reciprocal ordering method. From an ecological viewpoint, the bioindicator value of Corallinales was shown by the fuzzy c-means clustering data analyses. These species of Corallinales seems to be linked to two main environmental factors: salinity and temperature.