The 4-th order Runge-Kutta method in the complex plane is proposed for numerically advancing the solutions of a system of first order differential equations in one external invariant satisfied by the master integrals related to a Feynman graph. Some results obtained for the 2-loop self-mass MI are reviewed. The method offers a reliable and robust approach to the direct and precise numerical evaluation of master integrals.

PACS numbers: 11.10.--z, 11.10.Kk, 11.15.Bt, 12.20.Ds