In this study, the presence of anisakid nematodes in the European eels (Anguilla anguilla L.) was investigated. A total of 30 specimens of eels were caught by local fishermen from the Buyuk Menderes River, Turkey. Nematoda species of Raphidascaris acus was found from eels. This is the first record of R. acus from A. anguilla from Turkish waters. The ribosomal DNA (rDNA) internal transcribed spacer regions (ITS-1and ITS-2) and 5.8S of this parasitic species was amplified and sequenced. Also, all the nematodes were identified as R. acus based on nucleotide sequence comparisons. Pairwise comparison between the entire ITS regions and 5.8S of the R. acus isolates of A. anguilla (GenBank accession number: KT633862) and other R. acus isolates from Caspian Sea (KM047505), and Vistula Lagoon, Poland (AY603537) showed differences ranging from 0.0 to 1.9% intraspecific nucleotide differences, respectively. With the present study, R. acus infecting A. anguilla caught off the Aegean Region streams were characterized for the first time by sequencing of the rDNA ITS regions and 5.8S.