A surgical instrument case which includes a primary case which is substantially rectangular and has a pair of opposite side walls, a pair of opposite end walls and a bottom wall. A secondary case fits within the primary case, and the secondary case has at least one attachment element on an outside surface of the secondary case. The at least one attachment element is configured for connecting to at least one of the side walls and the end walls when the secondary case is mounted on an outside of at least one of the opposite side walls and the opposite end walls.