Bovine submaxillary mucin (BSM) was obtained from salivary glands through successive precipitations and dissolutions. It was labelled by acetylation with [1 –14C] acetic anhydride. Direct and continuous measurement of the total (reversible and irreversible) adsorption has been taken on muscovite mica, polyethylene, oxidized polyethylene, silicone and poly-(vinyl pyrrolidone) grafted silicone films. Force measurements between mucin layers adsorbed on two mica surfaces have been made in the distance range 0–600 nm. Adsorption/ desorption and force distance measurements allow us to distinguish between reversibly and irreversibly adsorbed protein molecules. The results also show that chemical modification of polymer surfaces enhances mucin adsorption.