The changes in structure and properties taking place in a set of tartaric acid-based polyamides and poly(ester amide)s upon hydrolytic degradation were examined. Poly(hexamethylene 2,3-di-O-methyl-L-tartaramide)s, either pure or containing minor amounts of succinate ester groups (less than or equal to 10%), were exposed to humidity or incubated in buffered water at pH 7.4 and 37 degrees C, and their thermal and mechanical properties were evaluated as a function of time. Both moisture uptake and hydrolysis induced a noticeable decay in the tensile properties of polymers. These effects were greatly enhanced by the presence of ester groups, whereas no large differences were noticed for changes in the enantiomeric composition. Variations in the glass transition temperatures and melting points appeared to be slight, whereas crystallinity clearly increased with incubation time. The latter effect was most apparent in poly(ester amide)s with a nearly racemic composition, in which a crystal-to-crystal transition was observed to take place upon degradation.