A theory of rotational Brownian motion of particles with surface charges is developed. It is based on an exact solution of the generalized Hubbard-Onsager equations. Dielectric friction in a polar solvent as well as a local increase of solvent viscosity due to electrostriction are taken into account. It is shown that for irregular surface charge distributions only two parameters are important for rotational Brownian dynamics: The total charge Q = ∑iqi, and the sum of squares of the surface charges, JB = ∑iq2i. Calculations show that the rotational diffusion coefficient depends strongly on the total surface charge, and may differ significantly from the ordinary Stokes value.