The purpose of this study was to assess the possibilities for bone reconstruction of an injectable calcium phosphate scaffold (ICPS) associated with a bone marrow (BM) graft after irradiation in a rat model. External irradiation was delivered to 12 out of 27 inbred rats. Three weeks later, four osseous defects were created per animal and were kept empty or filled with either ICPS alone, BM graft alone or with a mixture of BM and ICPS. Three weeks after implantation, bone specimens were studied under light microscopy and by scanning electron microscopy. Filling irradiated defects with ICPS alone was not accompanied by the formation of new bone. The BM graft associated with ICPS significantly increased ceramic degradation (p<0.01) and bone ingrowth (p<0.01) in the irradiated areas. The results are evidence for the meaning of the BM in driving the bone repair in irradiated animals.