CD44 hyaluronan receptor is present on large number of different cell type. It acts as one of the adhesion proteins, binding to hyaluronan and is known to play a part in cell migration from vessels in inflammation. The aim of this study was to examine the presence and distribution of CD44 in interface membrane in aseptic loosening. Immunohistochemistry (IHC) using human anti-mouse CD44 antibody studied 20 aseptically loosened interface samples. Extracted protein from all cases was examined by Western blot and RT-PCR. CD44 was detected in 85% of interfaces by IHC and the presence of protein confirmed by blotting and RT-PCR, which showed the mRNA level for CD44. CD44 was expressed by macrophage, multinucleated giant cells, mast cells and lymphocytes. Further studies are needed to characterise the role of this molecule in the inflammatory response to wear debris in aseptic loosening.