"Total hip replacement surgery (THR) is one of the most common surgeries performed in modern orthopedics, and in most cases offers a significant improvement in the quality of the patient's life. However, after some time, wear and osteolysis do appear, which leads to the need for revision surgery. With the indication being widened to a more young and active population, the need for extending the lifespan of the prosthesis is mandatory. Although several bearing surfaces have been studied over the years, and a lot of couplings are in use, the choice of the right combination of materials is still controversial. Biotribology tries to answer some of the current questions regarding the best bearing surface to use, being the branch of science and technology that studies friction, wear, and lubrication of different materials in the human body. In the present day, a large number of materials are in use for total hip replacement, but choosing the right combination of materials is still controversial, and is being done on one hand by the surgeon’s experience and on the other hand by the age and activity of the patient. The objective of this review is to try to present the main advantages and disadvantages of different materials and try to answer the most difficult question of them all: What is the right material to use for THR-bearing surfaces? "