  The quark-gluon mixed condensate $g<\bar q \sigma_{\mu\nu} F_{\mu\nu} q>$ is
calculated in the Gaussian approximation of the Field Correlator Method. In the
large N_c limit and for zero mass quarks one obtains a simple result, $m^2_0
\equiv \frac{g<\bar q \sigma_{\mu\nu} F_{\mu\nu} q>}{<\bar q q>} =
\frac{16\sigma}{\pi}$, where $\sigma$ is the string tension. For a standard
value $\sigma=0.18 GeV^2$ one obtains $m^2_0=1 GeV^2$ in good agreement with
the QCD sum rules estimate $m^2_0 = (0.8\pm 0.2) GeV^2$ and the latest lattice
result $m^2_0 \cong 1 GeV^2$.
