The members of the p24 protein family have an important but unclear role in transport processes in the early secretory pathway. The p24 family consists of four subfamilies (alpha, beta, gamma, and delta), whereby the exact composition of the family varies among species. Despite more than 15 years of p24 research, the vertebrate p24 family is still surprisingly ill characterized. Here, we describe the human, mouse, Xenopus, and zebrafish orthologues of 10 p24 family members and a new member that we term p24gamma(5). Of these eleven p24 family members, nine are conserved throughout the vertebrate lineage, whereas two (p24gamma(4) and p24delta(2)) occur in some but not all vertebrates. We further show that all p24 proteins are widely expressed in mouse, except for p24alpha(1) and p24gamma(5) that display restricted expression patterns. Thus, we present for the first time a comprehensive overview of the phylogeny and expression of the vertebrate p24 protein family.