In this study; the foley catheters were modified by plasma polymerization technique and coated with alginate gels. This modification processes were applied to prevent bacterial adhesion onto the foley catheter surfaces. Here the most effective parameters were evaluated as the plasma polymerization system power and plasma exposure time for the effective catheter surface modification. The obtained results showed that the plasma power affected hidrophilicity of the surface and wettability of the foley catheters was increased. The plasma exposure time increased the amount of EDA deposition over the catheter surfaces and then caused more hydrophilicity for the foley catheter surfaces also. In this study, the bacterial strain of E. Coli had a hydrophobic nature and therefore the increase in hydrophilicity of the surface of foley catheters decreased the adhesion risk for the E. Coli onto the catheter surfaces. As the numerical values of the obtained data; while the amount of bacterial colony formation unit was at 108 level initially, it was decreased down to 104-103 level by changing the surface hydrophilicities as expected