We compared the donor site morbidity in fifty-seven consecutive patients in whom a bone graft had been procured from the iliac crest through an incision parallel to the superior cluneal nerves and perpendicular to the posterior iliac crest (the study group) with that in fifty-three consecutive patients in whom the graft had been procured through an oblique incision parallel to the posterior iliac crest (the control group). Numbness, tenderness, and pain at the donor site one and six months postoperatively were assessed by means of an interview with the patient and a review of the records.The prevalence of symptoms in the control group was greater than that in the study group. At one month, thirty-nine patients (74 per cent) in the control group had numbness, compared with twenty-five (44 per cent) in the study group (p = 0.001). At six months, thirty-one patients (58 per cent) in the control group had numbness, compared with fourteen (25 per cent) in the study group (p = 0.0002). Thirty-six patients (68 per cent) in the control group and twenty-four (42 per cent) in the study group had tenderness over the incision at one month (p = 0.005), and twenty-seven (51 per cent) and eleven (19 per cent), respectively, had tenderness at six months (p = 0.0003). Forty patients (75 per cent) in the control group and forty-six patients (81 per cent) in the study group had deep pain in the region of the iliac crest at one month, compared with thirty-two (60 per cent) and thirty-one (54 per cent), respectively, at six months. The mean analog score for pain at the donor site was 7 of 10 points in the control group and 6 points in the study group (p = 0.001) at one month and 3 and 2 points, respectively, at six months (p = 0.001).