  Using the current world's largest data sample of psi(3770) decays, we present
results of a search for the non-DDbar decay psi(3770) -> KsKl. We find no
signal, and obtain an upper limit of Sigma(psi(3770) -> KsKl) < 0.07 pb at 90%
confidence level (CL). Our result tests a theoretical prediction for the upper
bound on B(psi(3770) -> KsKl) based on a charmonia-mixing model.
