Using density matrix equation, we calculate analytically as well as numerically the effect of the four-wave mixing (FWM) field on electromagnetically induced transparency (EIT) in the rubidium 5S1-2-5P3-2-SD5-2 Λ-type system with a two-photon probe field. The calculated results are in good agreement with Fulton’s experimental results in 1995Phys. Rev. A 52 2302.