Objective: To determine whether nuchal translucency thickness is influenced by the fetal position at ultrasound examination. Subjects: Transabdominal ultrasound examination for pregnancy dating and measurement of nuchal translucency thickness was performed at 10-14 weeks' gestation in all women attending the antenatal clinic of our hospital. During the examination special attention was paid to a change in fetal position from prone to supine or vice versa. Methods: For each fetus the nuchal translucency measurement was repeated when a positional change from prone to supine or vice versa was recorded. All measurements were recorded on hard copy. An image-scoring method was used and evaluated by three independent reviewers. Results: Eighty-five fetuses were included in this study. The mean nuchal translucency for supine fetuses was 1.91 mm compared with 1.93 mm for prone fetuses. The mean quality-score was 6.54 for supine fetuses and 6.55 for prone fetuses. This difference was not statistically significant. Conclusion: Fetal position has no influence on the measurement of nuchal translucency.