Objective: LAH was proposed to improve the implantation rate in FET cycles, but conflicting information exists in the literature with respect to the efficacy of AH in FET cycles. Methods: Embryo freezing was performed by vitrification at the cleavage stage 3 days after oocyte retrieval. Frozen embryos were thawed on the day of FET cycle. In the LAH group, zona thinning was performed by an experienced embryologist using a RI laser. During the operation, the outer half of the zona pellucida over a quarter of the diameter of the zona was removed. In the control group, embryos were replaced without LAH. Pregnancy and implantation rates were compared, p-value of <0.05 was considered statistically significant. Results: There were no differences in age of women at embryo freezing/thawing, body mass index, duration of infertility, primary/secondary infertility, cause of infertility, basal serum FSH concentration, cycle number, percentage of smokers or number of embryos frozen between the LAH group and the control group. The HMG dosage and duration and number of eggs retrieved/fertilized of the index stimulated cycle did not differ. However, pregnancy rates (43.5 vs 37.2%), and ongoing implantation rates (19.2 vs 16.3%) were higher in LAH treatment group compared to control, but these differences did not reach statistical significance. Conclusion: The findings of this study indicate that LAH treatment improves implantation and clinical pregnancy rates in women undergoing frozen-thawed embryo transfer. Furthermore, this treatment may be considered as a preferable strategy during the IVF treatment. However, this method does not seem to completely resolve the FET cycle.