Three children with adult cadaveric bone allografts for the treatment of bone malignancies are presented. Follow-up magnetic resonance (MR) imaging demonstrated decreased signal on T1-weighted imaging and increased signal on T2-weighted imaging in the allograft without clinical evidence of recurrent disease. These signal characteristics appear to be a normal finding in cadaveric bone allografts and should not be mistaken for recurrence. The finding may reflect persistent marrow necrosis within the allograft marrow cavity.