The aim of this study was to investigate the effects of a combination of porous bovine inorganic bone graft (Bio-Oss) and bilayer porcine collagen membrane (Bio-Gide) on refractory one-wall intrabony defects in dogs. Bio-Oss and Bio-Gide were applied into the refractory one-wall intrabony defect. The contralateral sites were used as controls (without the application of Bio-Oss and Bio-Gide). At 24 weeks after surgery, similar pocket depths were found in both groups. However, histologic observation revealed an infiltration of inflammatory cells in the control group caused by poor gingival architecture, whereas only a few of the experimental sites showed inflammatory infiltration. In addition to the healthy gingival tissue, periodontal tissue regeneration was observed in the experimental group. The combination of Bio-Oss and Bio-Gide was an effective treatment for refractory one-wall intrabony defects in dogs.