Gelatin/montmorillonite (MMT) hybrid nanocomposites with improved thermal and mechanical properties were prepared in a previous work. The swelling behavior (swelling rate, swelling kinetics, maximum solvent uptake, etc.) of the obtained composites was investigated. The results showed that the swelling process of the composites followed second-order kinetics identical to those of the original gelatin. The swelling rate and maximum solvent uptake were greatly suppressed by the presence of MMT and were dependent on the MMT content and pH of the gelatin matrix. Moreover, the swelling mechanism of the polyelectrolyte-intercalated nanocomposites was examined. (C) 2003 Wiley Periodicals, Inc.