  We report on the recent studies of leading order baryon-baryon interactions
in covariant baryon chiral perturbation theory. In the strangeness $S=0$
sector, one can achieve a rather good description of the Nijmegen $np$ phase
shifts with angular momenta $J\leq 1$, particularly the $^1S_0$ and $^3P_0$
partial waves, comparable with the next-to-leading order (NLO) heavy baryon
approach. In the strangeness $S=-1$ hyperon-nucleon sector, the best fit of the
36 scattering data is similar to the sophisticated phenomenological models and
the NLO heavy baryon approach.
