  The ${\eta}_{c}(1S)$ ${\to}$ $PP^{\prime}$ decays are the parity violation
modes. These decays can be induced by the weak interactions within the standard
model, and have been searched for based on the available experimental data. To
meet the needs of experimental investigation, the ${\eta}_{c}(1S)$ ${\to}$
$PP^{\prime}$ decays are studied with the perturbative QCD approach. It is
found that branching ratios are the order of $10^{-15}$ and less, which offers
a ready reference for future analyses.
