All pregnant women in The Netherlands are eligible for prenatal screening, including the combined test (CT) at approximately 12 weeks to determine the possibility of Down syndrome and the fetal anomaly scan (FAS) at approximately 20 weeks to detect structural anomalies. These tests are not routinely offered as part of prenatal care. The mean uptake of congenital anomaly screening tests has been approximately 27% for the CT and approximately 91% (80%–99%) for the FAS. This study was performed to investigate factors influencing the uptake of these screening tests, considering that uptake is associated with religious background, age, parity, socioeconomic status, ethnicity, and proficiency in Dutch. uthorized reproduction of this article is prohibited. 720 Obstetrical and Gynecological Survey Between 2009 and 2011, data were collected from 20 midwifery practices in The Netherlands. The response rate was 32% to 72%. Questions regarding CT and FAS uptake were posed to participants between 35 weeks' gestation and birth and at 6 weeks postpartum. Sociodemographic characteristics were obtained from a participant's profile in the initial questionnaire. Dichotomous variables were accepting or declining CT or FAS. Of the 7907 participants, 5216 women completed questionnaires about CT and FAS. The mean actual uptake for CTwas 23% (n = 1183) and 90% for FAS (n = 4679). The mean CT uptake of 808 women with a non-Dutch background was 29% compared with 22% (P < 0.001) for native Dutch participants. The mean uptake of FAS non-Dutch women was 89%, similar to that for the Dutch participants. Women who were Protestant or living in the eastern region were significantly less likely to have CT (odds ratio [OR], 0.32; 95% confidence interval [CI], 0.13–0.80; P = 0.015; OR, 0.44; 95% CI, 0.21–0.93; P = 0.033, respectively). Older women, those with income higher than the mean, or women from the first generation were significantly more likely to have the CT (OR, 2.00; 95% CI, 1.44–2.78; P < 0.001; OR, 1.97; 95% CI, 1.12–3.45; P = 0.018; OR, 2.91; 95% CI, 1.75–4.85; P < 0.001, respectively). For FAS among western non-Dutch women, those who were Protestant or Catholic were significantly less likely to have FAS (OR, 0.13; 95% CI, 0.05–0.34; P < 0.001; OR, 0.27; 95% CI, 0.09–0.81; P = 0.020, respectively). In the CT model for nonwestern women of non-Dutch background, older women or women with a limited proficiency in Dutch were significantly more likely to have CT (OR, 1.73; 95% CI, 1.25–2.39; P < 0.001; OR, 2.18; 95% CI, 1.34–3.56; P = 0.002, respectively). For FAS among nonwestern non-Dutch women, higher education had an independent positive impact on the uptake (OR, 1.47; 95% CI, 1.02–2.14; P = 0.041), whereas being Muslim or from the first generation had an independent negative impact on uptake (OR, 0.37; 95% CI, 0.19–0.72; P = 0.003; OR, 0.27; 95% CI, 0.13–0.59; P < 0.001, respectively). Being Protestant, having an income higher than the mean, and having a limited proficiency in Dutch were not independently associated with FAS uptake. This nationwide study on factors determining the uptake of CT and FAS found an association with income, parity, religious affiliation, ethnicity, age, education, and regional place of residence. These results may explain differences among women choosing or declining early and late screening but not the large variation in the test uptake among practices or between The Netherlands and other countries.