This paper proposes a method to simulate the effects of conductor surface roughness on conductor backed coplanar waveguides (CB-CPWs) using 3D full wave simulation tools. The varying heights for the random rough surface with specified autocorrelation function (ACF), root mean square height (h) and correlation length (l) are generated using MATLAB and this data is used by High Frequency Structure Simulator (HFSS) to model and simulate the CB-CPWs with rough conductor surfaces. The results show that both h and l influence overall the attenuation coefficient of the device and are consistent with the results of other studies in this area. Thus this method provides the designers with a technique to characterize the effect of conductor surface roughness for different types of transmission lines with varying substrates and extent of conductor roughness.