The aim of this study was to evaluate the clinical applicability of a ridge splitting technique for reconstruction of narrowed edentulous alveolar ridges for dental implantation. 41 patients with 47 edentulous areas were included in this study. After corticotomy of a rectangular buccal segment and about 3-4 weeks healing period, the alveolar ridge was splitted, implant was placed. The initial ridge width varied between 2.5 and 7.0mm, average was 3.99mm. 68 dental implants were placed, and the gap between the implants and the bone is filled with various bone graft material, or none. All splitted sites showed sufficient bone volume for insertion of the implants at the moment of implantation. Over 1 year of follow-up period, five implants(7.3%) had mobility in two patients, among them, 2 implants(2.9%) sustained infection and removed. And any other complications were not noted. Our conclussion is that ridge splitting of the narrow edentulous area is a reliable and safe procedure in horizontally deficient ridges.