Caspian Roach Rutilus rutilus caspicus is regarded as a valuable fish species for commercial food in the Caspian Sea. Genetic diversity of this fish species collected from two geographical areas (Gorgan Bay and Anzali Wetland) along the Iranian coastline of the Caspian Sea was examined by the analysis of RAPD markers. Using ten decamer primers, the total number of RAPD bands produced to both Gorgan Bay and Anzali Wetland populations were 94 bands. The percentages of polymorphic bands were comparable in Anzali wetland and Gorgan Bay, suggesting similar levels of polymorphism of the two populations. The value of genetic distance (0.04) among populations was small, despite the large geographic separation.