Giant cell tumor is a common bone neoplasm. We have initiated a prospective study for the treatment of giant cell tumor of bone by mixed (Autograft+Allograft) bone graft in the department of orthopaedics, Bangabandhu Sheikh Mujib Medical University (BSMMU), during January 2002 to March 2008. A total 28 patients of giant cell tumor of bone were operated. In this study out of 28 cases, male were 11(39.28%) and female were 17(60.72%). Female were predominant. Age of the patients ranging from 11 years to 49 years, mean age 27.03 years. More common in 21 years to 30 years 16(57.14%) of cases. Common sites of lesion were distal & proximal end of femur 11(39.28%), proximal end of tibia 6(21.43%), proximal humerus 3(10.71%) and distal radius 3(10.71%). Final clinical outcome of giant cell tumor of bone treated by thorough curettage of the cavity and filled with mixed bone graft (freeze dried radiation sterilized bone allograft+autogenous bone graft) in which success rate is 75%(21) and recurrence rate is 25%(7). P is <0.001. Follow up period was 4 months to 4 years. From this study it was realized that mixed bone graft is useful graft material for enhancing osteogenic potential as well as maintaining structural integrity for the treatment of giant cell tumor of bone.