Backward degenerate four-wave mixing (F W M) of coherent light beams in ferroelectric crystals LiNb03 and LiTa03 has been studied. The theory of F W M is developed taking into account the specific nonlinear response of electrooptic crystals. The results of calculation have been compared with the experimental data for continuous wave excitation of these crystals by He-Cd laser light. The possibility of phase conjugation and compensa-tion for static and time dependent phase inhomogeneitis via F W Min LiTa03 is demonstrated.