Background: Though prenatal genetic testing has been shown to have immense benefits, reports suggest it is not routinely done and is unavailable to many pregnant women in Nigeria. Factors associated with prenatal genetic testing as well as ethical aspects of consequent options available need to be assessed if prenatal testing is to be proposed to Nigerian women. Aims: This study evaluated the knowledge of genetic diseases and prenatal genetic testing, willingness to test, attitudes towards testing, use of common tests available as well as willingness to terminate affected pregnancies among antenatal clinic attendees in selected health facilities in an urban local government area (LGA) in Lagos, southwest Nigeria. Materials and Methods: This was a descriptive cross-sectional study. The study participants were 327 pregnant women in any of the three trimesters of pregnancy interviewed with structured questionnaires in two primary and one secondary health facility in the Local Government Area. Collected data was analysed using Epi-Info 7.2 statistical software. Results: Respondents’ mean age was 30 years ± 4.22. Majority of the respondents had post-secondary education, were experiencing their first pregnancy, and had no previous pregnancies or relatives with genetic diseases. More than half (69.4%) of the respondents had poor knowledge of genetic diseases. Almost all the respondents (97.6%) had poor knowledge of prenatal genetic testing. Majority of respondents (61.8%) were willing to undergo testing. Only 23.9% of the respondents had good attitude scores. Majority (26.9%) of the participants who had made use of a prenatal screening or diagnostic test had made use of ultrasound and blood test before three months of pregnancy. Only 10.1% of the population stated that they would opt to terminate affected pregnancies. Knowledge of genetic diseases significantly correlated with decision to terminate affected pregnancies. Conclusion: Education and approaches to ensure improved supportive care and treatment for children with genetic diseases should be explored in our environment.