Plasma surface modifications of homo-, co-, and terpolymers of propylene films in the presence of selected organosilicon and organotin compounds were investigated. For this, organosilan(stannan)e type compounds (such as vinyltriethoxysilane, 3-aminopropyltriethoxysilane, and tetraethylstannane) as well as organosiloxan(stannoxan)e type compounds (such as hexamethyldisiloxane and hexabutyldistannoxane) were exployed in plasma. Plasma surface modification of polyolefin films with organosilicon plasma has led to increase of the hydrophobicity, while the presence of organotin compounds in plasma produced less hydrophobic surfaces. Reaction of plasma-activated polyolefin films further with vinyltriethoxysilane-maleic anhydride oligomer also led to an increase in the hydrophobicity of polypropylene surfaces. It is observed that the degrees of swelling of (virgin, plasma-treated, and plasma-modified) polypropylene films in cyclohexanone strongly depend on the nature of the organoelement compounds used, organosilicon plasma causing lower degrees of swelling. The changes of surface properties observed are explained by different surface structures produced in plasma : in the case of organosilicon compounds, it is believed that poly(organosiloxane) and for organotin compounds poly(organotincarboxylate) fragments are formed primarily.