Acardiac twin syndrome is a rare complication affecting monozygotic twins, where one twin fails to develop normally and completely. In this report, we present an acardiac fetus that was seen for evaluation at 26 weeks of gestation. Initial routine ultrasound examination suggested anomalies. The first detailed ultrasound demonstrated a normal fetus with appropriate growth plus an acardiac twin with a hypoplastic lower limb with subcutaneous edema and intestine-like organ near it. The pregnancy was followed with serial ultrasonography and spontaneous delivery occurred at term. A normal infant was born, and after delivery of the placenta, at the chorionic plate of the placenta there was a sac with diminished fluid, containing some loops of the intestine. A thin cord of one vascular channel was attached to the common placenta. In our literature review, this type of acardiac fetus has not been reported previously.