A case for an electronic device includes: a protective cover having a side wall wherein the side wall significantly covers a side portion of the electronic device and the side wall includes an inner surface and an outer surface wherein the inner surface faces the electronic device and a longitudinal recess is formed on the inner surface; and a longitudinal insert member removably received in the longitudinal recess. The longitudinal insert member includes an inner wall and an outer wall and the inner wall faces the electronic device. The longitudinal insert member is provided with a plurality of holes and the holes are separated by a plurality of partitions. The structure by the holes is effective in protecting the electronic device from impact or shock.