OBJECTIVE To investigate the theory that ultrasound guidance during ET improves clinical outcomes. DESIGN Systematic review of prospective, randomized, controlled trials comparing ultrasound with clinical touch methods of embryo catheter guidance. SETTING Infertility centers. PATIENT(S) 5,968 ET cycles in women. INTERVENTION(S) Embryo transfer with or without ultrasound guidance. MAIN OUTCOME MEASURE(S) Meticulous electronic (e.g., PubMed, EMBASE, CENTRAL) and hand searches were performed to locate trials. Primary outcome measures were the live-birth, ongoing pregnancy, and clinical pregnancy rates. Secondary outcome measures were the implantation, multiple pregnancies, and miscarriage rates. In addition, the incidences of ectopic pregnancies and difficult transfers were evaluated. RESULT(S) Twenty-five studies were retrieved, of which five were excluded. Meta-analysis of the remaining studies (5,968 ET cycles in women) was conducted by using the Mantel-Haenszel method (fixed-effect model). There was a significantly increased chance of a live birth (odds ratio [OR] = 1.78, 95% confidence interval [CI] = 1.19 to 2.67), ongoing pregnancy (OR = 1.51, 95% CI = 1.31 to 1.74), clinical pregnancy (OR = 1.50, 95% CI = 1.34 to 1.67), embryo implantation (OR = 1.35, 95% CI = 1.22 to 1.50), and easy transfer rates after ultrasound guidance (OR = 0.68, 95% CI = 0.58 to 0.81). There was no difference in multiple pregnancy, ectopic pregnancy, or miscarriage rates. CONCLUSION(S) Ultrasound-guided ET significantly increases the chance of live birth and ongoing and clinical pregnancy rates compared with the clinical touch method.