Viscosities of aqueous solutions of bovine serum albumin (BSA) at different temperatures were carefully measured in a common glass capillary Ubbelohde viscometer in the concentration range from dilute down to extremely dilute concentration regions. The adsorption effect occurred in viscosity measurements were theoretically analyzed and discussed. The theory based on the Langmuir isotherms could adequately describe the existing data. The influence of temperature on the adsorption of BSA solution was discussed and a simple adsorption model was proposed. The conformational change of BSA macromolecules happened both in the bulk solution and on the inner surface of glass capillary. (c) 2007 Wiley Periodicals, Inc.