We use three-dimensional surface topography analysis for evaluating waterjet generated surfaces. The waterjet generated surface is separated into smooth and striation zones, where striation influence is negligible in the smooth zone. It is found that the smooth zone has a random, moderately isotropic texture, with the height distribution nearly Gaussian. The effects of cutting speed, depth of cut, and abrasive size on the surface roughness are studied for the smooth zone and striation zone separately. This provides useful information for controlling process parameters to obtain smooth finished surfaces. Spectral analysis is used to investigate the surface striation and machine structure vibration. It is found that forced vibration of the mechanical structure strongly influences striations generated in the waterjet machining system.