Until 1996, scientific information about groundfish assemblages on southern Adriatic trawlable bottoms almost exclusively referred to the western side of the same basin (Italian waters). During 1996, for the first time, a summer trawl survey was carried out along the full South Adriatic area. A total of 93 demersal fish species was obtained and the ‘species abundance (biomass)/sam‐pling stations’ matrix was analysed by means of cluster analysis. The analysis was useful to discriminate the shelf and slope assemblages on both sides of the South Adriatic and to compare biodiversity. This was determined with univariate ecological indices (diversity, equitability) and graphical methods (ordinary, cumulative, and partial dominance; abundance/biomass comparison curves). Fish assemblage biodiversity was higher on shelf bottoms of the eastern Adriatic side (Albanian waters) than the western shore (Italian waters). The highest catch yields, referring to the main “target”; trawl fishery species, were usually found along the Albanian shore.