The remodelling of bone grafts depends to a large extent upon the type of graft and the condition of the recipient site. We applied 99mTc-phosphate scintigraphy in a follow-up study on cases treated by bone grafting, and quantitative analysis of the scintigram by computer to make clear the difference of remodelling time or the process of acceptance between a cancellous and a cortical bone grafting or due to various graft and conditions. The result revealed that the grafted bones which were smoothly adapted for subsequent growths or functions could restore normal accumulation ratios by 36 months after the grafting. When the cancellous bone was grafted to grafting beds with good conditions such as osteotomy site in the cases with coxarthrosis deformans or congenital dislocation of the hip, it could attain the quickest recovery of the normal accumulation ratio. The next quickest recovery of accumulation ratio was attained by grafting the cancellous bone to the grafting beds with poor conditions such as osteomyelitis, pseudoarthrosis, and bone tumor. The third best accumulation ratio could be attained when the cortical bone was grafted to grafting beds with good conditions, while the slowest recovery to normal accumulation ratio was noted when the cortical bone was grafted to grafting beds with poor conditions.