This morphological and genetic study is performed on several types of amphipods from coastal waters compared to species outside the Romanian Black Sea basin. The evaluation and interpretation of morphological characters highlighted that the group of romanian amphipod genera (Euxinia, Pontogammarus, Compactogammarus, Obesogammarus) are probably evolving. The separation of more primitive forms such as Echinogammarus and Dikerogammarus is confirmed by some aspects of molecular genetics analysis.