  A theory for the effects of nonmagnetic disorder on the magnetic pair
breaking rate $\alpha$ induced by paramagnetic impurities in quasi
two-dimensional superconductors is presented. Within the framework of a
strong-coupling theory for disordered superconductors, we find that the
disorder dependence of $\alpha$ is determined by the disorder enhancements of
both the electron-phonon coupling and the spin-flip scattering rate. These two
effects have a tendency to cancel each other. With parameter values appropriate
for Pb_{0.9} Bi_{0.1}, we find a pair breaking rate that is very weakly
dependent on disorder for sheet resistances 0 < R < 2.5 kOhm, in agreement with
a recent experiment by Chervenak and Valles.
