Physically crosslinked hydrogels are formed upon mixing equal amounts of aqueous solutions of dextran grafted with L-lactic acid oligomers and dextran grafted with D-lactic acid oligomers. In this paper, the dex-lactate hydrogels are analyzed by X-ray diffraction to provide evidence that hydrogel formation occurred through stereocomplex formation. First, the stereocomplex formation of monodisperse lactic acid oligomers was studied and comparison with published results of poly(lactic acid) was made. It was clearly demonstrated that stereocomplexes were formed between oligomers of opposite chirality. The data for these monodisperse lactic acid oligomers were used to interpret the results obtained with the clex-lactate hydrogels. X-ray diffraction measurements demonstrated that in the hydrogels stereocomplexes were formed between the lactic acid oligomers of opposite chirality.