A 3.3 kb cDNA encoding the complete amino acid sequence of a calcium/calmodulin regulated protein phosphatase has been isolated from a Drosophila eye disc cDNA library. The predicted protein of 560 amino acids (molecular mass 62 kDa) is 73-78% identical to human PP2B isoforms. The cDNA hybridised to the X-chromosome at cytological position 14D1-4. Two transcripts of 3.5 kb and 3.0 kb were expressed during embryonic development, their levels being highest in the early embryo. The larger transcript was also clearly present in adult females. This pattern of expression indicates a role for calcium/calmodulin regulated protein phosphatase in embryonic development.