Mermaid Syndrome, or Sirenomelia, is an extremely rare congenital disorder characterized by the fusion of the lower limbs, often accompanied by severe urogenital and gastrointestinal malformations. This systematic review aims to provide a comprehensive overview of the etiology, clinical presentation, diagnostic challenges, and management strategies for Mermaid Syndrome. A detailed analysis of case reports and research studies published in medical and scientific journals was conducted, focusing on cases reported over the past four decades. The review highlights that the etiology of Sirenomelia remains unclear, with theories suggesting multifactorial causes, including genetic, environmental, and vascular abnormalities. Prenatal diagnosis using ultrasonography and advanced imaging techniques is critical for early detection. Management is complex, requiring a multidisciplinary approach encompassing surgical intervention, supportive care, and rehabilitation. While survival rates remain low due to associated complications, advancements in neonatal care and reconstructive surgeries have shown promise in improving outcomes for select cases. The findings emphasize the need for further research to better understand this enigmatic condition and enhance treatment modalities.