Since its identification 60 years ago as a ubiquitous component of the body of mammals, hyaluronic acid has been widely studied, primarily in the fields of medicine and biology. On the other hand, our research has dealt with hyaluronic acid as a chemical intermediate in the synthesis of novel lubricious coatings, and in this connection data were needed on stability of aqueous solutions of the polymer over a range of temperatures from 25–100°C. The investigation reported here provides that information, obtained by exposing samples in sealed ampules in baths a controlled temperatures and determining the resultin change in viscosity of the solutions. Data of this kind have not previously been reported on sodium hyaluronate free from the proteins and other organics normally associate with the polymer in its natural environment. © 1994 John Wiley & Sons, Inc.