  The amount of late decaying massive particles (e.g., gravitinos, moduli)
produced in the evaporation of primordial black holes (PBHs) of mass
$\Mbh\la10^9 $g is calculated. Limits imposed by big-bang nucleosynthesis on
the abundance of these particles are used to constrain the initial PBH mass
fraction $\beta$ (ratio of PBH energy density to critical energy density at
formation), as: $\beta\la 5\times10^{-19} (\xp/6 10^{-3})^{-1} (\Mbh/10^9 {\rm
g})^{-1/2} (\bar{\Yp}/10^{-14})$; $\xp$ is the fraction of PBH luminosity going
into gravitinos or moduli, $\bar{\Yp}$ is the upper bound imposed by
nucleosynthesis on the number density to entropy density ratio of gravitinos or
moduli. This notably implies that such PBHs should never come to dominate the
cosmic energy density.
