mRNA and genomic DNA were isolated from adult Cylicocyclus nassatus, and the mRNA was reverse transcribed. The cDNA was PCR amplified using degenerate primers designed according to the alignment of the beta-tubulin amino acid sequences of other species. To complete the coding sequence, the 3' end was amplified with the 3' RACE, and for amplification of the 5' end the SL1-primer was used. The cDNA of the beta-tubulin gene of C. nassatus spans 1429 bp and encodes a protein of 448 amino acids. Specific primers were developed from the cDNA sequence to amplify the genomic DNA sequence and to analyse the genomic organisation of the beta-tubulin gene. The complete sequence of the genomic DNA of the beta-tubulin gene of C. nassatus has a size of 2652 bp and is organised into nine exons and eight introns. The identities with the exons of the gru-1 beta-tubulin gene of Haemonchus contortus range between 79% and 97%.