The crystallization behavior of a high molecular weight equimolar mixture of optically pure poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) is investigated in order to analyze the factors affecting its stereocomplexation. PLLA/PDLA blend films at 1 : 1 molar ratio were prepared by solvent casting and isothermally crystallized from the as cast samples (cold-crystallization) and from molten samples (melt-crystallization). Their crystallization behavior was analyzed by means of DSC, PLOM, WAXD and FTIR. The experimental evidence indicates that stereocomplexation is much more efficient in cold crystallized samples than in melt crystallized samples. To achieve exclusive stereocomplexation with a high degree of crystallization from high molecular weight polylactides (M_w > 2 × 10⁵ g mol⁻¹), samples must be crystallized above the melting point of the homocrystals, the thermal treatment must increase the number of nucleation points and adverse transesterification reactions must be avoided.