Our objective was to explore the feasibility of using both transvaginal endoscopy and transabdominal needle embryofetoscopy for early prenatal diagnosis. Our experience with both terminating and continuing pregnancies is presented in this report. Following the granting of informed consent, patients undergoing first-trimester terminations were invited to participate in this program. Initially, a transvaginal endoscope was used in these studies: a rigid fiberoptic endoscope 30 cm in length with a diameter of 1.5 mm. Subsequently, a specially designed 16-gauge, double-barrel needle sheath, equipped with a 0.8-mm fiberoptic endoscope and a customized 27-gauge heparinized needle were used. In either case, the endoscope was passed under ultrasound guidance into the exocelomic space, from which the anatomy of the embryo/fetus was scrutinized. For continuing pregnancies, patients were selected when at high risk for various dysmorphology syndromes. To date, we have successfully performed more than 300 transvaginal procedures, successfully visualized the fetus in 95% of cases, and verified sonographically suspected anomalies in all of the five cases studied. We have also performed 20 transabdominal procedures, 15 in terminating pregnancies and five in continuing pregnancies, without adverse effects. Our experience establishes the feasibility of first-trimester diagnostic endoscopy. This new development is expected to serve as a prelude for further studies that attempt to diagnose and treat congenital diseases in early pregnancy. Potential applications include gene and stem-cell therapy at a time when the embryo is immunologically naive.