Morphological changes in immiscible polymer blends have been studied in shear flow using an original method based on quenching following deformation of molten samples. Relaxation effects were expected to be negligible during cooling and, hence, the real shear-induced blend microstructure could be analyzed. The method has been successfully applied to follow morphological changes of immiscible blends composed of polystyrene and relatively high amounts of high-density polyethylene during creep experiments. The final steady-state morphology appeared to be intimately related to the applied shear stress and total deformation. Coalescence as well as large deformation and orientation of the dispersed phase particles have been observed depending on the flow conditions. The variations with time of the blend rheological properties and morphological observations are in qualitative agreement. (C) 2000 The Society of Rheology. [S0148-6055(00)00103-6].