A Drosophila gene encoding a homologue of vertebrate arrestin was isolated by subtractive hybridization and identified as a member of a set of genes that are preferentially expressed in the visual system. This gene encodes a 364-amino acid protein that displays greater than 40% amino acid sequence identity with human and bovine arrestin. Interestingly, the Drosophila homologue lacks the C-terminal sequences that were postulated to interact with rhodopsin during the quenching of the phototransduction cascade in the vertebrate visual response. These findings are discussed in terms of invertebrate phototransduction. The Drosophila gene was mapped cytogenetically to chromosomal position 36D1-2, near the ninaD locus. However, the arrestin gene does not appear to be the ninaD locus, as sequence analysis of three ethylmethane sulfate-induced ninaD mutant alleles reveals no alteration in amino acid sequence.