Complications of the donor site after the harvest of corticocancellous bone graft from the posterior iliac crest are very common. The most common are chronic donor site pain, tenderness, and sensory disturbances. This study investigates the results of the midline, lumbar fascia splitting approach for harvesting bone graft in lower lumbar spine fusion and compares them with the classic separate incision approach. A retrospective study of 107 patients compares two groups. The first group of 56 patients (35 males and 21 females with an average age of 41.8 years) had bone graft taken by splitting the two layers of the lumbar fascia down to their attachment to the iliac crest. The second group of 51 patients (29 males and 22 females with an average age of 43.7 years) had a separate incision over the iliac crest. In the first group, 82.1% had no tenderness, 8.9% mild, 7.1% moderate, and only 1.8% severe tenderness over the donor site. In the second group, 45.1% had no tenderness, 21.6% mild, 17.6% moderate, and 15.7% severe tenderness over the donor site. Five patients of the separate incision group (9.8%) had a lump in the donor site compared with none in the “same incision” group. Sensory disturbances over the donor site were found in 5.4% of the first group and in 21.6% of the second group. Harvesting bone graft from the posterior iliac crest for lower lumbar spine fusion through a midline, fascia splitting approach was found superior to the traditional, separate incision approach.