Objective: To analyze the clinical outcome o f horizontal ridge augmentation using autogenous block grafts covered with anorganic bovine bone mineral (ABBM) and a bioabsorbable collagen membrane. Material and methods: With severe horizontal bone atrophy, a staged approach was chosen for implant placement following horizontal ridge augmentation(fig 1,2). A block graft was harvested from the symphysis, and secured to the recipient site with fixation screws. The width of the ridge was measured before and after horizontal ridge augmentation. The block graft was subsequently covered with ABBM and a collagen membrane. Following a tension-free primary wound closure and a mean healing period of 6-8 months, the sites were re-entered, and the crest width was re-assessed prior to implant placement.