This paper reports on the first aphids' cuticular proteins. One gene (Mpcp1) was obtained by screening a cDNA library of Myzus persicae with antibodies to a lepidopteran cuticle protein. MpCP1 presents a putative signal peptide, a central extended R&R domain, flanked by N- and C-terminal repeats of alanine, tyrosine and proline. The mRNA of Mpcp1 could be detected in a larval and in adult stages. Primers based on Mpcp1 allowed isolating and comparing cuticle protein genes from five aphid species, but not from whitefly or thrips. Comparison revealed a high degree of similarity. Data from this paper suggest that this cuticle protein family is typical and predominant to aphids. The conformation of these cuticle proteins and the significance on particular properties of aphid cuticle is discussed.