Abstract: Background: Malaria caused by Plasmodium vivax is often considered less severe than infections caused by other Plasmodium species. However, recent evidence suggests that P. vivax can lead to severe complications, including hepatic dysfunction and transudative ascites. This case report describes an unusual presentation of severe P. vivax malaria in a 14-year-old female, characterized by persistent vomiting, loose stools, jaundice, and high-grade fever with rigors. Case Presentation: The patient, who had a history of acute gastroenteritis, was admitted with symptoms persisting for 8 days. Initial findings included anemia, elevated liver enzymes, and transudative ascites. Diagnostic imaging revealed splenomegaly, an enlarged liver, and mild ascites. Ascitic fluid analysis was consistent with transudative ascites and showed elevated adenosine deaminase (ADA) levels. The diagnosis of P. vivax malaria was confirmed by identifying gametocytes in the peripheral blood smear. Treatment with intravenous Sulbactam and Artemisinin resulted in significant clinical improvement. Discussion: This case highlights the potential for severe manifestations of P. vivax malaria, including jaundice, hepatic dysfunction, and transudative ascites. The patient's presentation underscores the need for a high index of suspicion for malaria in endemic regions, especially when clinical symptoms overlap with other tropical diseases. The resolution of symptoms with appropriate treatment supports the diagnosis and emphasizes the importance of timely intervention.