The wire saw process is widely used for silicon wafer production with high yield and low surface damage in solar cell and microelectronics industries. The wire saw process is used to machine brittle materials in the ductile regime where high yield and low surface damage are desired. The wire saw process is also used to cut concrete and rocks in civil engineering. In this study, an experimental parametric study was conducted by varying process parameters to determine surface roughness damage. Ductile regime material removal by trans-granular failure and brittle fracture by inter-granular failure are observed in electron micrographs of the cut surfaces. A damage model that relates the roughness damage to process parameters was derived. The damage model predicts the roughness damage satisfactorily. The model shows that the roughness damage is proportional to the ratio of feed speed to wire speed. Improvement in the efficiency of the process without increasing the roughness damage can be attained by increasing the feed speed proportionally to wire speed. Wire tension does not affect roughness damage. Roughness damage, however, is affected by properties of the wire. Wires having smaller grit radius and small grit spacing cause less roughness damage.