Objectives: The aim of this study was to assess the reliability of the mock transfer during in vitro fertilization process Method: A case-control study was conducted on 134 patients included in IVF/ICSI cycles. From the hysterometry obtained during the mock transfer, the ideal embryo replacement site, i.e. two cm from the uterine fundus has been determined. Results: Significant differences were noted between the area estimated from the mock transfer and the area where the embryo was deposited during the actual embryo transfer. In fact, 15.9% of the patients had a difference between four and six cm, and 32% of the patients returning for a subsequent transfer had at least 2 cm of difference between the embryo deposit zones. This difference was significant (P < 0.00) Conclusion: More than ultrasound guidance, the challenge with embryo transfer is to be able to minimize variations in the length of the uterus. This would make it possible to determine the ideal transfer depot area without multiple manipulations.