Objective: To histologically evaluate the effect of Bio-Oss particles as bone grafts in combination with membrane-technique. Materials and Methods: Six small biopsy specimens were retrieved from augmentation sites, treated with Bio-Oss particles and Bio-Gide resorbable collagen membranes and titanium membranes in 6 patients. The Donath’s hard tissue section and micro grinding technique was adopted, and Leval Laczko staining method was used. Results: The histological results showed Bio-Oss particles were easily distinguished from the newly formed bone, but new bone was formed among different particles of Bio-Oss, no connective tissue was found. Intimate contact between newly formed bone and particles of the graft was present. Conclusion: Bio-Oss appears to be highly biocompatible and osteoconductive, and can be used with success as a bone substitute in combination with guided bone regeneration membrane technique.