Plasmodium vivax has been increasingly reported to cause various serious manifestations of malaria including thrombocytopenia, cerebral malaria, acute renal, hepatic and pulmonary dysfunctions with reports of high morbidity and mortality by cerebral involvement. To evaluate the degree of severe complications in Plasmodium vivax such as cerebral malaria, hepatic dysfunction, renal complications and pulmonary complications in Plasmodium vivax  infection. The study group included patients presenting with fever and associated symptoms characteristic of malarial infection.Diagnosis of malaria was made on the basis of clinical features,peripheral blood smear examination, Q.B.C  and Rapid antigen detection test. Other  laboratory investigations were  also taken into consideration. Out of 1,737 patients positive for Plasmodium vivax infection, a total of 65 patients had atypical symptoms.32 patients presented with cerebral symptoms ,Hepatic funtions were affected in 31 patients. Renal dysfunction was observed in 1 patient and gastrointestinal complications in 1 patient..No patient in our study group presented with pulmonary symptoms. In cases of febrile illness with features of malaria, thrombocytopenia or neurological dysfunction not only Plasmodium falciparum but also Plasmodium vivax should be considered  as differential diagnosis. Early detection,prompt management and adequate antimalarial treatment can reduce significant morbidity and mortality associated with severe complications of Plasmodium vivax infection.