Purified human umbilical hyaluronate and a commercial preparation of rooster comb hyaluronate (Healon®) intended for intra‐articular viscosupplementation did not demonstrate the same degree of boundary‐lubricating ability as bovine synovial fluid or its purified lubricating mucin, lubricin (p < 0.01). Boundary lubrication was measured in vitro in an arthrotripsometer oscillating natural latex against polished glass under a load of 0.35 MPa with an entraining velocity of 0.37 mm/s. The two hyaluronate solutions possessed the same hyaluronate concentration as synovial fluid, but Healon was 4.5 times more viscous. Present practice of viscosupplementation therapy for degenerative joint disease is limited and fails to implicate the important role of synovial mucin. Boundary lubrication provided by synovial mucin, independent of its viscosity, is not replicated by hyaluronate hydrogels. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 40, 414–418, 1998.