  We calculate the heavy-to-light form factors in the relativistic quark model
with heavy infrapropagators. Their q^2-dependence in the physical region is
defined by two parameters: the "infrared" parameter \nu characterizing the
infrared behavior of the heavy quark and the mass difference of the heavy meson
and heavy quark E=m_H-M_Q. It is found that the values of the D\to K(K^*) and
D\to \pi(\rho) form factors at q^2=0 are in excellent agreement with the
available experimental data and other approaches whereas these values for B\to
\pi(\rho) transitions are found to be larger than those of several other
models. The obtained form factors are used to calculate the widths of the
semileptonic decays of B and D mesons. The comparison of our results with the
available experimental data and other approaches is given
