The hydrolytic behavior of monolayers of enantiomeric poly(lactide)s (PLAs), d-PLA and l-PLA, and their mixtures spread at the air/water interface has been studied in order to elucidate the hydrolytic stability on the stereocomplex formation of enantiomeric components. The rate of hydrolysis was recorded by a change of occupied area when the monolayer is maintained at a constant surface pressure. Under a basic subphase, the hydrolysis of the (d-PLA/l-PLA 50150 by mol.%) mixture monolayer was much slower than those of each homopolymer. This result suggests that the stereocomplexed monolayer is more hydrolysis-resistant than each homopolymer one. (c) 2005 Elsevier B.V. All rights reserved.