Abstract: A disposable seat liner (10) that covers a shopping cart's child seat (20) that includes a cart handle (22). The liner (10) consists of a liner seat bottom (24) configured to cover the child's seating area of a shopping cart (26). A liner right side (28) and a liner left side (30) are integrally formed with the seat bottom and folded upward. A liner handle end (32) overlaps the cart handle (22) and is also integrally formed with the liner seat bottom (24). A liner seat back (42) jointly overlaps the cart's seat and the cart's basket upper portion, and is permanently attached with heat-sealed joints (34) to the liner right side and left side on adjacent edges, thereby forming a disposable protective cover to assure isolation from microorganisms found on the shopping cart's child seat and handle.