Ultrahigh molecular weight polyethylene (UHMWPE) is usually difficult to be melt processed due to severe intermolecular entanglement in its melt. In this work, we reported the development of a poly(amido amine) (PAMAM) dendrimer (G1) and its derivatives with different terminal groups which showed promising feasibility for aiding UHMWPE melt processing. The rheological, crystalline, and mechanical properties of the blends were investigated comprehensively. The addition of the dendritic modifiers to the UHMWPE matrix resulted in a significant decrease in melt viscosity, thus an obvious enhancement of the processability. The dynamic analysis of the mechanical properties and rotation-rheological test indicated a disentanglement effect of the UHMWPE melt molecules was generated by the PAMAM dendrimer (G1) and its derivatives. Furthermore, the PAMAM dendrimer (G1), as an internal lubricant, was uniformly distributed in the UHMWPE matrix. The heteronucleation effect of the PAMAM dendrimer (G1) with its derivatives led to a higher degree of crystallinity, smaller crystallites in the matrix and enhanced tensile strength in the UHMWPE blends. POLYM. ENG. SCI., 57:153-160, 2017. (C) 2016 Society of Plastics Engineers