Summary: We introduce a second order in time modified Lagrange-Galerkin (MLG) method for the time dependent incompressible Navier-Stokes equations. The main ingredient of the new method is the scheme proposed to calculate in a more efficient manner the Galerkin projection of the functions transported along the characteristic curves of the transport operator. We present error estimates for velocity and pressure in the framework of mixed finite elements when either the mini-element or the \(P2/P1\) Taylor-Hood element are used.