his study presents the first results about the genetic polymorphism and diversity among the five Egyptian Bulinus truncatus populations, Giza (GZ), Damietta (DM), Behera (BH), Fayoum (FY) and lab bred strain (LB), using the inter - simple sequence repeats PCR (ISSR - PCR). A total of 85 bands, unique, polymorphic and monomorphic were obtained using 10 ISSR primers. Out of them, 28 bands were polymorphic. Among B. truncatus populations, the highest polymorphism (57.1%) was revealed by the primer ISSR1, followed by that revealed by ISSR7 (40%). However, the lowest polymorphism was 16.6% and resulted from application of ISSR6 and ISSR 8 primers. ISSR5, ISSR7, ISSR9 and ISSR10 primers revealed four unique bands of size 389, 199, 139 and 154 bp respectively for FY population. All bands resulted from application of ISSR4 primer were monomorphic. Genetic similarity and relationship between the five populations were detected using cluster analysis. The high genetic variability obtained from ISSR markers showed diverges of FY population from the others which may be interpreted by located Fayoum region in an isolated area from the Nile Valley. It was noted the presence of a high level of genetic similarity between GZ and LB populations, that may be due to the origin of LB was from Giza governorate. Our results have provided evidence for the usefulness of ISSR markers to analyze genetic variab ility among B. truncatus populations.