Three water masses in winter sad five in eutnmer are identified from three-dimensional interpretation of the hydrographic pera}ters collected from the southeastern Mediterranean off the Egyptian coast.The volume and mean depth in each bivariate class with potential temperature tauge 0.2 of 0.5℃ and salinity range of 0.1 have been estimated during winter and summer, The resulting statistics are presented on a pair of characteristic diagrams, each having potential temperature es ordinate and salinity es abscissa.In winter and summer seasons s primary and big mode appears at a potential temperature 13.4℃ and salinity 38.75.It occupies the deeper classes below 1 000 m deep and is called the deep water mass of the East Mediterranean.It is found that the mean potential temperatures and salinities are 14.14℃ and 38.818 in winter and 14.14℃ and 38.807 in summer.