  We propose a solution to the mu/B_mu problem in gauge mediation. The novel
feature of our solution is that it uses dynamics of the hidden sector, which is
often present in models with dynamical supersymmetry breaking. We give an
explicit example model of gauge mediation where a very simple messenger sector
generates both mu and B_mu at one loop. The usual problem, that B_mu is then
too large, is solved by strong renormalization effects from the hidden sector
which suppress B_mu relative to mu. Our mechanism relies on an assumption about
the signs of certain incalculable anomalous dimensions in the hidden sector.
Making these assumptions not only allows us to solve the mu/B_mu problem but
also leads to a characteristic superpartner spectrum which would be a smoking
gun signal for our mechanism.
