Thirty-two patients with radiographic evidence of scaphoid nonunion were preoperatively evaluated by magnetic resonance imaging (MRI), then observed intraoperatively for punctate bleeding of the fragments. Although MRI and intraoperative findings matched in 19 patients, there was no correlation in 13 patients. While 7 of these latter patients showed normal MRI but no punctate bleeding during the operation, the remaining 6 had preoperative MRI of avascularity but punctate bleeding during the operation. After internal fixation and bone grafting, all but 1 of these 13 patients achieved union. We conclude that the diagnosis of avascular necrosis should only be made when both MRI and intraoperative findings indicate avascularity.