  Semileptonic decays of Lambda_b and Lambda_c baryons are studied within the
Relativistic Three-Quark Model using finite heavy quark mass values. Employing
the same parameters as have been used previously for the description of
exclusive decays of heavy baryons in the heavy quark limit we calculate the six
form factors of the process and the corresponding decay rates. Our calculation
shows that the ``finite mass'' corrections are important in heavy-to-light
transitions and are not negligible in heavy-to-heavy transitions.
