Over the years, extensive research has been dedicated to exploring both metallic and non-metallic biomaterials to develop effective implants for medical use. Despite these efforts, finding a single material that satisfactorily fulfills all biological and mechanical compatibility criteria for integration with the human body remains a complex and unresolved challenge. Implant failures are often attributed to a range of issues. These include inadequate inflammatory responses, which can hinder healing; susceptibility to bacterial infections, which may lead to systemic complications; and mechanical challenges such as corrosion, wear, and loosening of the implant. Such failures not only compromise patient outcomes but also frequently necessitate costly and invasive revision surgeries. To tackle these significant hurdles, surface engineering has emerged as an essential strategy aimed at enhancing the long-term integration and functionality of implants within the biological environment. By modifying the surfaces of biomaterials, researchers can improve biocompatibility, reduce the risk of infection, and promote better bonding with surrounding tissues. This chapter delves into various surface modification techniques employed on commonly used metallic biomaterials, including stainless steel, magnesium, titanium, and cobalt-chromium alloys. We will explore the mechanisms and benefits of these techniques, as well as the implications for the durability and performance of implants in clinical applications. Through this discussion, we aim to shed light on the innovative approaches that are paving the way for the development of more reliable and effective biomedical devices.