Anorectal atresia (ARA) is a congenital anomaly with an incidence of 1:1500 to 1:5000 in newborns. This malformation can be isolated, but is often associated with multiple congenital anomalies. Until recently, the diagnosis was often made in the third trimester of pregnancy or even after birth but, according to a review, it was established that prenatal diagnosis can be made even in the first trimester. Early diagnosis is essential for the management and planning of birth and postpartum treatment. We present the case of a fetus diagnosed with ARA at 12+0 weeks at the first-trimester ultrasound anomalies scan. The karyotype was performed and the result was normal. ARA was diagnosed and considered isolated since further detailed examinations performed in the second and third trimesters found no other anomalies. After birth, at 36 weeks, the diagnosis was confirmed as low anorectal atresia with perineal fistula. The newborn was scheduled for surgery at 3 months of life.