It is widely claimed that parallel robots are intrinsically more accurate than serial robots be-cause their errors are averaged instead of added cumulatively, an assertion which has not been properly addressed in the literature. This paper addresses this void by comparing the kinematic accuracy of two pairs of serial-parallel 2-DOF planar robots. Only input errors are considered and all robots are optimized for accuracy, the only constraint being that they cover a given de-sired workspace. The results of this comparison seem to confirm that parallel robots are less sen-sitive to input errors than serial robots.