Morphometric and meristic specifications of Abramis brama orientalis of the Caspian Sea and Aras Dam Reservoir was studied in the year 2002. For this purpose, 40 morphometric attributes, 16 meristic attributes and 37 specifications in relation to the proportions of speciality of morphometric attributes of the Abramis brama orientalis were evaluated from the two habitats. Anova, factor and discriminant function analyses were conducted on the data. According to results the average coefficient of variation in morphometric, meristic and proportion of speciality of morphometric attributes for Abramis brama orientalis of Caspian Sea was 22.85, 3.24 and 7.68 and for Abramis brama orientalis of Aras Dam Reservoir was 17.45, 3.53 and 15.27. The Abramis brama orientalis of the two areas showed meaningful differences in 35 morphometric factors, 6 meristic factors and 25 factor of proportion of the speciality of the age had significand differences (P〈O.05). Factor analysis showed that the Abramis brama orientalis of the two habitats had 80.62% of changes in 7 factors of first morphometric attributes, 73.65% of changes in the 9 factors of the first proportion of morphometric specialities and 46.52% of changes in the 4 factors of the first meristic attribute. We showed that, fork length, standard length, proportion of head length to the standard length, number of scales of the lateral line, number of scales under the lateral line, number of scales above the lateral line, radius of dorsal fin and number of dorsal fins can be used to separate population of the fish from the two habitats. The first two factors of proportion of speciality of morphometric and meristic attributes causes total separation of the two populations. We found different in morphometric specialities between the two specialities of morphometric and meristic attributes. It is suggested that different environmental conditions have led to the differences in the populations of the fish in the Caspian Sea and Aras Dam Reservoir.