Purpose: The purpose of this study is to evaluate the clinical stability of implants placed with a ridge splitting technique through the investigation of the survival rate and marginal bone loss of implants. Methods: 34 implants were placed in 20 patients with the ridge splitting technique. 8 out of 34 implants were placed with the nonsubmerged approach. 26 out of 34 implants were placed with the submerged approach. Guided bone regeneration (GBR) and bone graft were applied in 13 implants. Results: A prosthetic procedure was performed on average 7.9 °æ 3.0 months after placement. The average follow up period was 4.2 °æ 2.1 years. During the follow up, the cumulative survival rate of implants was 100%. The mean marginal bone loss of implants was 1.57 °æ 1.44 mm at the mesial side and 1.42 °æ 1.48 mm at the distal side. In non-submerged implants, the mean marginal bone loss was 1.17 mm and 0.70 mm on the mesial and the distal sides, respectively. In submerged implants, the loss was 1.74 mm and 1.59 mm on the mesial and the distal sides, respectively. The difference between the two groups was not statistically significant (P > 0.05). Complications during implant placement surgery, buccal bone dehiscence, fenestration, and buccal bone plate fracture, occurred with 5 implants. In those implants, the mean marginal bone loss was 1.73 mm and 1.90 mm on mesial and distal sides, respectively. In implants without complications, the mean marginal bone loss was 1.57 mm and 1.26 mm on the mesial and the distal side, respectively. The difference between the two groups was not statistically significant (P>0.05). Conclusions: Within limits of this study, considering the results of this study, the ridge splitting technique has a long-term clinical stability to place the implant at the narrow alveolar ridge. [THE JOURNAL OF THE KOREAN ACADEMY OF IMPLANT DENTISTRY 2011;30(1):1-8]