Abrasive waterjet machining is a novel method of machining complex shapes and profiles. Surface roughness is a widely used machining characteristic to define the quality of the machined components. This present study reports the effects of workpiece material thickness, abrasive mass flow rate and standoff distance on surface roughness while performing abrasive waterjet machining. A L9 Taguchi array is used for the design of experimentation signal to noise ratio and analysis of variance is carried out. The experimental results show that the most influential parameter affecting surface roughness is workpiece thickness.