RESUMEN
Acardiac twinning affects 1 in 100 monozygotic twin pregnancies and 1 in 35,000 pregnancies overall. This condition is characterized by the absence or rudimentary development of fetal heart, and associated with various anomaly. The presence of an acardiac twin requires the normal (or "pump") twin to provide circulation for itself, as well as the acardiac sibling. The acardiac malformations are uniformly fatal in the affected twin, and mortality in the co-twin is as high as 55%. The principal perinatal problems associated with acardiac twinning are pump-twin congestive heart failure, maternal hydramnios, and preterm delivery. We recently experienced a case of acardius anceps associated with a normal male infant, so present with a brief review of the literature.