Introduction: The acardiac acephalic fetus or twin reversed arterial perfusion (TRAP) sequence, is a rare complication specific to monochorionic twin pregnancy. It is characterized by the development of arterio-arterial and veno-venous anastomosis leading to one of the twins__ampersandsignrsquo; predominance. Objective: Our objectives are to describe this pathology and its etiopathogenic factors and emphasize the need for an early diagnosis and adapted therapeutic management to improve the prognosis of the pump twin. Clinical case study: We report the case of an acardiac fetus from a twin pregnancy of a 32 years old-patient, low socio-economic level. She was admitted at 40 weeks of amenorrhea according to the date of her last period, in the expulsion phase, giving vaginal birth to a first twin of normal appearance and then an acardiac fetus weighing 1000g. Presentation: In our study, the prevalence rate of TRAP is estimated at 1 in 44,000 births. Its diagnosis is based on Doppler ultrasound from the 1st trimester which allows visualizing the reversal of vascular flow in the acardiac recipient fetus and during the 2nd trimester, the MRI allows to confirm the diagnosis. In our case, the pregnancy was poorly followed, no ultrasound examination was performed and the diagnosis of the acardiac fetus was made at the time of delivery. Conclusion: An acardiac fetus is never viable. However, several complications can affect the transfusion twin, which underlines the importance of an early prenatal diagnosis allowing adequate therapeutic management to improve the prognosis of the healthy twin.