The effect of blending crosslinked linear low-density polyethylene (cLLDPE) on the rheological properties and foam processability of linear low-density polyethylene was studied. A small addition of cLLDPE, which had a low density of crosslink points, enhanced strain-hardening behavior in the elongational viscosity to a great degree, although it had little effect on the steady-state shear viscosity. The enhanced strain hardening reduced heterogeneous deformation during foaming. As a result, a foam with a uniform cell size distribution was obtained.