Objectives. Maxillofacial prosthetic materials are used to replace facial parts lost through disease or trauma. Silicone rubbers are the materials of choice, however it is widely accepted that these materials do not possess ideal properties. The objective of this study was to assess the properties of two commercially available silicone rubber maxillofacial materials after plasma surface treatment with two different gases (oxygen and argon). Methods. Specimens of five commonly used maxillofacial materials were prepared in specially designed copper molds according manufacturer instructions. Tear strength, tensile strength, percentage elongation and hardness were determined for each material. Plasma surface treatment was done using Dielectric Barrier Discharge DBD (open technique) with two gases (oxygen and argon). Results. Tear strength, tensile strength, percentage elongation and hardness of both materials tested (Techsil S 25 and Cosmesil M511) showed a statistically significant increase (p<0.05) after plasma surface treatment with both gases (oxygen and argon). Conclusions. Plasma surface treatment DBD (open technique) of silicone maxillofacial material by oxygen and argon plasma showed no radical differences in the properties of maxillofacial prosthetic materials. Moreover, a plasma surface treatment DBD (close technique) may be considered in another study for comparison.