This chapter reviews the evidence regarding uterine position and catheter position on embryo transfer outcomes, and discusses techniques that optimize these factors. While firm catheters may aid in catheter placement with difficult transfers, the increased force and rigidity of the catheter may induce endometrial trauma. A meta-analysis found that firm catheters are associated with lower pregnancy rates than soft catheters. In order to minimize difficult transfers, trial transfers can be preformed. Trial transfers prior to ovarian stimulation map the cervical angle and the uterine depth. Varying position of the catheter at the time of embryo deposition is associated with differences in pregnancy rates and ectopic pregnancy rates. The introduction of transabdominal ultrasound-guided embryo transfers has enabled precise catheter placement and is associated with improved outcomes. Ultrasound-guided embryo transfers have provided insight into variables that affect the success of transfers, such as the optimal location for embryo deposition.