The chemical and physical effects incurred at the surface of biaxially oriented polypropylene film during silent discharge plasma treatment have been investigated using XPS, NMR, TOF-SIMS, and AFM techniques. It is found that chain scission accompanied by oxidative attack leads to the formation of low molecular weight oxidized material which agglomerates into globules at the surface due to a large difference in interfacial free energy between the underlying hydrophobic substrate and the oxygenated overlayer.