In the Black and the Azov seas were found 140 species of Amphipoda, concern to 73 genera, 29 families and 3 suborders. Investigations of taxonomical diversity of Amphipoda from the Black and the Azov seas were made. Indices of Average Taxonomical Distinctness Δ+, variability in TaxD index Λ+, Cluster analysis and MDS ordination were made. Taxonomical structure of the Black and the Azov seas Amphipods by indices Δ+ hierarchical aligned and close to total taxonomical list of Amphipoda these seas. By indices Λ+ Amphipoda both the Azov and the Black seas close to expected in average level of variability of structure of taxonomical tree. Two regions – north-west of the Black sea and east of the Black sea were select by indices Δ+, Λ+ and method of MDS ordination. North-west of the Black sea characterize small taxonomical diversity (little of genera and families, many of species). Presence of estuary of big rivers and lagoons with small salinity waters was reason of small taxonomical diversity of north-west region of the Black sea. Amphipoda of East coast of the Black sea have big taxonomical diversity, but a little of species number. The reason – a small shelf, near to coast noted quick increase of depth and small of soft ground. Similarity of taxonomical lists of Amphipoda of north-west of the Black sea and Azov sea was identify by cluster analysis. Ponto-Caspian species live in estuary of big rivers and lagoons with small salinity waters and they characterize of taxonomical structure impoverishment in relation to taxonomical evenness of all Amphipods of the Black and the Azov seas.