Electrophoresis is often used to measure the "average" zeta (ΞΆ ) potential on particles. However, it has been found by previous researchers that in making predictions of colloidal forces and stability, the distribution of ΞΆ potential on the particles is important. This paper provides a straightforward method for measuring charge nonuniformity on colloidal spheres. It is shown that if the charge or ΞΆ potential is random on a group of spheres, each covered with N equal-area patches, then the average magnitude of the dipole moment on the spheres is 0.92Ο ΞΆ / β N, and the average magnitude of the quadrupole moment is 1.302Ο ΞΆ / β N, where Ο ΞΆ is the standard deviation of ΞΆ potential over the surface of individual spheres. This is true for any random distribution of ΞΆ potential, and the results emphasize that "random" implies nonuniform. It is demonstrated that since typical translational mobility measurements are much less sensitive to random charge nonuniformity than rotational mobility measurements, the latter measurement is better suited for measuring the second moment (Ο ΞΆ ) of ΞΆ potential. Monte Carlo simulations were done to confirm and extend the analytical results.