Implant surface micro-topography has been of great interest for many years. Scientific evidence indicates that the micro-roughness of the implant is one of the regulatory factors for osseointegration, and roughness within a certain range has been proven to present the strongest bone responses. The so-called moderately rough micro-topography has been applied to most of the commercially available implants of today and has shown high clinical success rates, especially in compromised bone quality sites. This chapter will focus on the importance of micro-topography on implant osseointegration by exploring the experimental and clinical evidence available. Furthermore, the recent topics regarding micro-topography in relation to marginal bone maintenance will be briefly discussed.