  The elastic pi-N scattering amplitude in the isospin limit is calculated in
the framework of heavy baryon chiral perturbation theory, up to the third
order. Threshold parameters like scattering lengths, volumes, effective ranges,
etc. are compared with data. All relevant low energy constants are fixed from
the available pion-nucleon data. A clear improvement in the description of data
is observed, when going from the first two orders in the chiral expansion to
the third one. The importance of even higher orders is suggested by the result.
