  I examine the position of the ice line in circumbinary disks heated by steady
mass accretion and stellar irradiation and compare with the critical semi-major
axis, interior to which planetary orbits are unstable. There is a critical
binary separation, dependent on the binary parameters and disk properties, for
which the ice line lies within the critical semi-major axis for a given binary
system. For an equal mass binary comprised of 1 M$_{\odot}$ components, this
critical separation is $\approx 1.04 $AU, and scales weakly with mass accretion
rate and Rosseland mean opacity ($\propto [\dot{M}\kappa_R]^{2/9}$). Assuming a
steady mass accretion rate of $\dot{M} \sim 10^{-8} {\rm M_{\odot} yr^{-1}}$
and a Rosseland mean opacity of $\kappa_R\sim 1 {\rm cm^2 g^{-1}}$, I show that
$\gtrsim 80%$ of all binary systems with total masses $M_{\rm tot} \lesssim 4.0
M_{\odot}$ have ice lines that lie interior to the critical semi-major axis.
This suggests that rocky planets should not form in these systems, a prediction
which can be tested by looking for planets around binaries with separations
larger than the critical separation with \emph{Kepler} (difficult) and with
microlensing.
