In this work, an influence of bovine serum albumin proteins grafting on the surface properties of plasma-treatedpolyethylene and poly-L-lactic acid was studied. The interaction of the vascular smooth muscle cells with the modifiedpolymer surface was determined. The surface properties were characterized by X-ray photoelectron spectroscopy,atomic force microscopy, nano-LC-ESI-Q-TOF mass spectrometry, electrokinetic analysis, and goniometry. One of themotivations for this work is the idea that by the interaction of the cell with substrate surface, the proteins will forman interlayer between the cell and the substrate. It was proven that when interacting with the plasma-treatedhigh-density polyethylene and poly-L-lactic acid, the bovine serum albumin protein is grafted on the polymer surface.Since the proteins are bonded to the substrate surface, they can stimulate cell adhesion and proliferation.