Side chain modification of polyolefins applying a copper-mediated click chemistry strategy is described. First, a bromo-functionalized polyethylene (PE-Br) are synthesized via ring-opening metathesis polymerization of cis-cyclooctene followed by quantitative hydrobromination. Subsequently, the bromide moieties of the functional PE-based polymer are converted into azide groups via simple nucleophilic substitution. Success of the click reaction is demonstrated by using low molar mass and polymeric alkyne functional click components, namely pyrene alkyne and polystyrene alkyne, respectively. The intermediates at various stages and final polymers are characterized by H-1 NMR, Fourier transform infrared, Gel permeation chromatography, and differential scanning calorimetry analysis.