ABSTRACT. – The present study aimed at evaluating spatial and temporal patterns of diversity in Mediterranean rocky reef fish assemblages. With this objective, we tested the followinghypotheses: i) assemblages of different depth ranges differed in terms of species composition and patterns of diversity, ii) within each depth range, patterns of diversity varied depending on the spatial scale examined and iii) they followed seasonal and inter-annual dynamics. Three habitats related to different intervals of depths were studied within a rocky coastal area during a year one period using visual census techniques. Alpha diversity, at different spatial and temporal scales, and beta diversity, between and within different habitats, were evaluated. 65 valid taxa were determined during the study period, 33 in 25-30 m deep assemblages, 38 in 10-15 m deep assemblages and 35 in 0-5 m deep assemblages. The results showed that patterns of alpha and beta diversity of the studied fish assemblages, such as their seasonal dynamics, significantly changed in relation to depth and that these differences remained constant between years.