Large-amplitude oscillatory shear (LAOS) has been applied to a lamellar, microphase-separated, low molecular weight poly(styrene-b-isoprene) diblock copolymer melt to induce macroscopically aligned morphologies. Small-angle X-ray scattering and dynamic mechanical testing were performed to characterize the states of orientation. The perpendicular orientation was induced by applying LACS at a fixed frequency (1 rad/s) and strain amplitude (100%) at:nigh temperatures. LAGS applied at the same frequency and strain amplitude but at lower temperatures induced the parallel orientation. Interestingly, intermediate temperatures produced a mixed morphology containing both parallel and perpendicular orientations. The linear viscoelastic responses of the parallel and perpendicular morphologies were related to the LAGS conditions necessary to produce the perpendicular, the parallel, and the mixed parallel-perpendicular morphologies. Specifically, two frequencies were defined using the linear viscoelastic responses : omega(Pd-Pl＇) where G＇(parallel) = G＇(perpendicular) and omega(Pd-Pl") where G"(parallel) = G"(perpendicular). The uniaxial morphology induced by LACS was found to correspond to that morphology which subsequently produced the lowest linear viscoelastic moduli, both elastic and storage. Analysis also showed that the viscoelastic response of the mixed parallel-perpendicular morphology could be approximated by a linear combination of the responses for samples wholly in the parallel and perpendicular orientations. Similar alignment and rheological results were obtained for a blend containing the diblock copolymer and 10 wt % homopolystyrene.