Titanium alloys are materials commonly used in the manufacture of components in aeronautical industry due to a unique combination of properties such as high mechanical strength, low density, high corrosion and oxidation resistance. However, titanium alloys machinability is compromised due to its low thermal conductivity and high chemical reactivity with tool materials, especially with ceramics (major materials applied in in grinding process). Therefore, is essential to study and define the most suitable cutting conditions that includes of dressing operation, that directly affects the component surface quality. In this sense, the calculation of measurement uncertainty associated with Ra roughness parameter of the Ti-6Al-4V alloy was developed after dressing the grinding wheel under different conditions. The expression was based on proposed methodology by Guide to the expression of uncertainty in measurement. Experimental tests were developed with a silicon carbide grinding wheel conditioned under two dressing conditions: an aggressive overlap ratio Ud = 3, and a smooth overlap ratio condition, Ud = 12. Cutting speed (30 m/s), workspeed 7.5 m/min and radial depth of cut (30 µm) were kept constant in all the tests. Surface roughness (Ra parameter) and measurement uncertainty associated with it were the output variables analyzed. The results showed a reduction of 32.9% in Ra parameter due to a change in grinding wheel conditioning from an aggressive condition (Ud = 3) to a smooth one (Ud = 12). From analyzed results in terms of measurement uncertainty, it was possible to identify that under Ud = 12 dressing condition the lower Ra roughness results were obtained.