The present study was focused on both the new distributional records and karyological data for Arvicola amphibius from the European part of Turkey. The karyotype of the Eurasian water vole was investigated by examining its metaphase chromosomes. The diploid number of chromosomes (2n), the fundamental number of chromosomal arms (FN) and the number of autosomal arms (FNa) were found to be 36, 64 and 60, respectively, for one female individual from a single locality in the European part of Turkey. It was determined that A. amphibius has 2n = 36 chromosomes, consisting of seven metacentric, three submetacentric, three subtelocentric and four acrocentric chromosome pairs. The X chromosome was a large submetacentric. The present study confirmed the previous results with regard to 2n. However, comparison of our findings with those of other authors indicates that there are karyotypic differences among the chromosomes. These differences were related to the morphology of chromosomes. Additionally, we reported external and skull measurements and new distributional records from six localities for the Turkish water vole. The measurements presented in this study conform to those of samples examined by other authors