The goal of this chapter is to define concepts and methods currently used to study the corrosion behavior of biomaterials in physiological conditions. One of the interesting points of corrosion of biomaterials is that they must be designed to fulfill different physical and chemical requirements within the human body. For instance, ceramic biomaterials are designed, sometimes, to accomplish a bone growth task. Alternatively, bioceramics are also employed to provide high wear resistance to implant surfaces with the lowest corrosion activity in biological environment. Depending on the part of the human body where the biomaterial is implanted, the corrosion process and chemical interaction with body fluids can be accelerated, and consequently, the product of these reactions can have a negative effect in the health of the patients. For this reason, the chapter is also focused on explaining how to study the interaction between biomaterial surface and body fluids as well as the existing methods to prevent corrosion phenomena that could lead to affect human health.