Although the Mediterranean is considered to be one of the oldest regions in the world, its borders are still the subject of discussion and research. This paper aims to contribute to the definition of the Mediterranean by studying the perception of its spatial coverage in Croatia and its links to the physical and socio-cultural attributes of space. The research was conducted by using the cognitive map method on the sample of 200 participants. The result was a broad border zone separating the so-called "real" Mediterranean from areas which are not part of the Mediterranean. This zone is somewhat similar to a fuzzy set, representing a gradual transition between two ends belonging to a certain set. The research indicates that the congruence of perception of the borders of the Mediterranean is the largest along the Dinaric Alps (northwest – southeast), except in Istria, and the coastal spread along the entire Croatian littoral. The results also indicate that factors relating to the natural environment take precedence over socio-cultural factors in the perception of borders of the Mediterranean