The adsorption of polyacrylamide fractions of different molecular weights and degrees of hydrolysis on hydroxyapatite and dental enamel, as well as their influence on the kinetics of dissolution of the latter, are studied at a constant pH under well controlled conditions. It is shown that the adsorbed polymers can slow down the dissolution process. The intensity of the inhibition effect follows the characteristics of the adsorption layer. The inhibition increases with the molecular weight of the polymers and their degree of hydrolysis. These behaviors are well interpreted with the model of apatite dissolution recently proposed, which supposes the formation of a cationic semipermeable layer, formed by the adsorption of calcium ions at the apatite interface.