Rheological properties under elongational flow for blends of polypropylene (PP) and low-density polyethylene (LDPE) were studied. The strain-hardening behavior in the transient elongational viscosity was found for the blend even though LDPE droplets were dispersed in the matrix PP. Moreover, the drawdown force, defined as the force required to stretch a polymer melt uniaxially at the non-isothermal condition, was enhanced by the LDPE addition, which was prominent when LDPE shows low viscosity.