  Motivated by the successes of covariant baryon chiral perturbation theory in
one-baryon systems and in heavy-light systems, we study relevance of
relativistic effects in hyperon-nucleon interactions with strangeness $S=-1$.
In this exploratory work, we follow the covariant framework developed by
Epelbaum and Gegelia to calculate the $YN$ scattering amplitude at leading
order. By fitting the five low-energy constants to the experimental data, we
find that the cutoff dependence is mitigated, compared with the heavy-baryon
approach. Nevertheless, the description of the experimental data remains
quantitatively similar at leading order.
