We report the use of a free vascularised iliac bone graft in the treatment of 21 patients (19 men and 2 women) with an avascular nonunion of the scaphoid in which conventional bone grafting had previously failed. The mean age of the patients was 32 years (23 to 46) and the dominant wrist was affected in 14. The mean interval from fracture to the vascularised bone grafting was 39 months (9 to 62). Pre-operative MRI showed no contrast enhancement in the proximal fragment in any patient. Fracture union was assessed radiologically or with CT scans if the radiological appearances were inconclusive. At a mean follow-up of 5.6 years (2 to 11) union was obtained in 16 patients. The remaining five patients with a persistent nonunion continued to experience pain, reduced grip strength and limited range of wrist movement. In the successfully treated patients the grip strength and range of movement did not recover to match the uninjured side. Prevention of progressive carpal collapse, the absence of donor site morbidity, good subjective results and pain relief, justifies this procedure in the treatment of recalcitrant nonunion of the scaphoid.