The behavior of osteoblastic cells on two different amino-functionalized plasma polymer layers was investigated. A positive effect on cell adhesion, spreading and mobility of the adhesion protein vinculin was observed. The cells showed a very flat morphology so they literally melted with the surface structure. It was demonstrated that the chemical surface modification is dominant over surface topography. Comparative analyses revealed that not the density of the amino groups, but rather the general positive surface charge is responsible for the cell-attractive potential of the plasma layers.