Morphologies in the vicinity of interfaces of immiscible linear-low-density polyethylene/poly(methyl methacrylate) (LLDPE/PMMA) = 80/20 (w/w) blends containing polyethylene-block-poly(methyl methacrylate) (PE-b-PMMA) were investigated by transmission electron microscopy (TEM). It was found that crystalline lamellae of polyethylene was oriented vertically to the interface between LLDPE and PMMA phases in LLDPE/PMMA blends containing PE-b-PMMA. In addition, length of lamellae oriented vertically to the interface became longer with increasing content of PE-b-PMMA in the blends.