The Middle Paleolithic blade phenomenon is now acknowledged as part of Middle Paleolithic technological variability. These blade assemblages are now largely documented and well dated in some areas such as the Levant and Northwestern Europe, while inother regions, they are only briefly reported. In the Southern Caucasus, Middle Paleolithic blade assemblages have been identified along time ago 2 and needed re-examination in the light of recent analytical methods and questions. Our study, based on the technological and techno-economic approach, enabled us to compare these blade productions with the Early Levantine Mousterian assemblages already well pub-lished, and to investigate the role of the site in the settlement pattern of these Southern Caucasus Middle Paleolithic populations. The clear technological affinities of the Djruchula assemblageswith the Early Levantine Mousterian from Hayonim lower E and F, Hum-mal Ia and Abou Sif, suggest their belonging to the same techno-complex. It seems that the High Caucasus Mountains served as anatural barrier and limited the expansion of the Middle Paleolithic leptolithic tradition to the North (Russian plains, Central Europe) where these industries are still unknown.