Variations in the course of the inferior gluteal nerve and artery were observed in Japanese cases (4/94 sides). In these variation cases, the inferior gluteal nerve exited the pelvis from the upper edge of the piriformis (suprapiriformis foramen) in 4/4 sides (4.26%). In 2/4 sides (2.13%), the normal inferior gluteal artery was not observed, except that a fine artery exited the pelvis from the inferior piriformis foramen to form an “arch” with the superior gluteal artery under the gluteal maximus in 1/4 side. Moreover, in 1/4 side, a twig of the internal pudendal artery exited pelvis from inferior piriformis foramen and distributed to the surrounding tissues. The present observations of the inferior gluteal nerve and artery course are very important and useful for surgeons and nurses.