Biomaterials are considered one of the fundamental pillars in the development of modern medical devices and implants. They are used in the manufacturing of artificial joints, dental implants, vascular stents, and intraocular lenses. These materials aim to restore the functions of organs and tissues while ensuring biocompatibility with the human body. Concept of Biomaterials and Biocompatibility Biomaterials are defined as materials designed to interact with biological systems for therapeutic or diagnostic purposes. Biocompatibility is one of their most important properties, referring to the ability of a material to perform its intended function without causing adverse reactions in the surrounding tissues. Types of Biomaterials and Their Applications Biomaterials vary according to their properties and medical applications. The most important types include: Metals and Alloys: Such as titanium and cobalt-chromium alloys, which are used in artificial joints, dental implants, and fracture fixation devices. Ceramics: Such as alumina, zirconia, and hydroxyapatite, which are used in dental crowns and bone grafts. Polymers: Such as silicone, PMMA, and polyethylene, which are used in the manufacturing of catheters, lenses, and joint liners. Biodegradable Materials: Such as PLA, PGA, and magnesium alloys, which are used in surgical sutures and temporary screws that gradually degrade inside the body after performing their intended functions. Major Medical Applications Biomaterials are widely used in orthopedic surgery for hip and knee joint replacement, and in dentistry for supporting artificial teeth. They are also employed in the manufacturing of vascular stents, heart valves, and intraocular lenses. These applications contribute significantly to improving patients' quality of life and restoring essential biological functions. Challenges and Future Developments Despite the significant progress in this field, several challenges remain, including corrosion, wear, inflammation, and implant-associated infections. Meanwhile, recent research is focusing on developing smart materials, biodegradable materials, nanostructured surfaces, and 3D-printed implants to improve biocompatibility and enhance the performance of medical implants. Conclusion Biomaterials represent an important bridge between engineering and medicine, contributing to the development of innovative medical solutions and improving the efficiency of medical devices and implants. Collaboration among biomedical engineers, materials engineers, and medical professionals plays a vital role in developing safer and more effective implants, thereby supporting the future of healthcare.