We report a process for the formation of inverted ferroelectric domain regions in LiTaO3. This process involves ion exchange followed by domain inversion by a uniform electric field. The resultant periodic domain structure is applicable to first order quasi-phase-matched second-harmonic generation. In first order periodically poled crystals of Z-cut LiTaO3, initial results have shown bulk conversion efficiencies of up to 3%/(W-cm). A second- harmonic conversion of 3 mW of blue wavelength power was observed from waveguide devices made on these crystals.