  Moduli fields, a natural prediction of any supergravity and
superstring-inspired supersymmetry theory, may lead to a prolonged period of
matter domination in the early Universe. This can be observationally viable
provided the moduli decay early enough to avoid harming nucleosynthesis. If
primordial black holes form, they would be expected to do so before or during
this matter dominated era. We examine the extent to which the standard
primordial black hole constraints are weakened in such a cosmology. Permitted
mass fractions of black holes at formation are of order $10^{-8}$, rather than
the usual $10^{-20}$ or so. If the black holes form from density perturbations
with a power-law spectrum, its spectral index is limited to $n \lesssim 1.3$,
rather than the $n \lesssim 1.25$ obtained in the standard cosmology.
