  The existence of non--universal soft masses is the most general situation in
supersymmetric theories. We study the consecuences that this situation has for
the low--energy sparticle spectrum. In particular, we analize in detail the
contribution to the scalar mass renormalization group equations of the $U(1)_Y$
D--term. We obtain analytic expressions for the evolution of masses of the
three generations and these allow us to show that such a contribution can
produce important modifications on the spectrum. The necessity to avoid flavour
changing neutral currents does not constrain this result. Finally, we discuss a
realistic example in the context of string theory where the departure from
universality is large.
