Background: Anencephaly is the most common type of Neural Tube Defect (NTD). Babies born with anencephaly usually die within hours or a few days after birth. The prevalence of anencephaly cases reaches 5.1 per 10,000 births in the world. There is no therapy for patients with anencephaly, but this condition can be detected early by ultrasonography. Case: 17-year-old girl with abdominal complaints that are getting bigger. She has pregnant and the fetus had suspected anencephaly. The patient’s vital signs were good and laboratory examination showed a slight increase in leukocytes, proteinuria, and leukocyturia. The ultrasound examination results gestational age was 29/30 weeks, and the radiological examination by a radiologist expert had similar results. The baby girl was born with a weight of 1,568 grams and an Apgar score of 2-3. On examination, prominent brain tissue was visible. The baby was treated for three days at Trenggalek General Hospital and survived for four days. Conclusion: The aetiology and pathophysiology of anencephaly are still unclear, but risk factors such as environmental, genetic, maternal and fetal conditions encourage this condition. Detection of NTDs can be done early in pregnancy using ultrasound. Early prevention must be carried out, such as regular consumption of folic acid to prevent the occurrence of NTDs. In this case, the occurrence of NTDs is thought to be due to the condition of the mother who is too young, socioeconomic factors, low consumption of folic acid and lack of knowledge and information about the importance of prevention in NTD cases.