A storage tray for storing mailpieces for a mail-handling machine, which storage tray comprises a support wall, a first jogging wall adjacent and perpendicular to said support wall, and a second jogging wall adjacent and perpendicular both to said support wall and to said first jogging wall, these three walls meeting at a single junction point, the support wall being provided with at least one first slot for allowing motor-driven feed members of the mail-handling machine to pass through.