We have used cloned chicken cDNA sequences for alpha- and beta-tubulin to investigate tubulin gene organization in Drosophila melanogaster. Experiments using genomic Drosophila DNA from several sources indicate that there are at least four copies each of the alpha-tubulin gene and the beta-tubulin gene. In situ hybridization experiments show that both the alpha- and beta-tubulin multigene families have dispersed arrangements on the chromosome. Genes for alpha-tubulin have been localized at chromosomal bands 67C, 84B/C, 84D and 85E, while genes for beta-tubulin have been detected at bands 60A/B and 85D. alpha-Tubulin and beta-tubulin chicken cDNA sequences can be used to select a specific mRNA species from a complex mixture which translates in vitro into alpha- or beta-tubulin protein. RNA blot hybridization using the cloned chicken cDNA sequences as probes shows that the alpha- and beta-tubulin messages detected are clearly different in length, with the message for alpha-tubulin measuring approximately 2000 bases and the message for beta-tubulin containing approximately 1800 bases.