Abstract: The present invention relates to an artificial synovial fluid composition that mimics the tribological and biochemical properties of human, osteoarthritic synovial fluid for in vitro testing of implantable materials. The artificial synovial fluid comprises new-born calf serum or alpha-calf serum (iron-free or iron-supplemented) that contains a specific total protein concentration, specific protein constituent fractions (albumin, ?-1 globulin, ?-2 globulin, ?-globulin, and ?-globulin), specific trace element concentrations (Ca, Mg, inorganic P, and Fe), and a specific low-molecular weight peptide concentration important for in vitro testing of implantable materials. In addition, the artificial synovial fluid contains a hyaluronic acid concentration and level of osmolality (preferably using phosphate buffered-saline solution) to mimic the thermal stability (transition mid-point temperature, enthalpy, and entropy) and pH level as measured clinically.