A flexible intramedullary nail is disclosed that is manufactured from a biocompatible rigid material and having a substantially cylindrical hollow body, a leading segment with an entry hole at a distal end and at least one securing means and a trailing segment having a trailing edge and an attachment mechanism. The body has at least one flexible center section, each having at least one slot to provide flexibility. In one embodiment the at least one slot follows a sinuous, serpentine path to form a plurality of interlocking teeth that can follow a helical or a concentric path. Each of the slots has a proximal end and a distal end, with the proximal end being spaced from the trailing segment and the distal end being spaced from the leading segment. When multiple slots are incorporated, the proximal end of a slot is spaced from a distal end of a subsequent slot. The first of the at least one flexible center section and a second of the at least one flexible center section can be separated by a non-slotted section. The nail can be used with a flexible insertion shaft or a locking shaft.