Plasmodium vivax malaria is an endemic disease in Korea, which rarely causes severe complications including those occurring in the cerebrum. There are limited numbers of complicated cases that have been reported around the world. We experienced a case of vivax malaria with cerebral complication: cognitive impairment and ataxia. A 55-year-old female with diabetes mellitus presented to the emergency department with acute fever of two days' duration. She did not have any history of travelling abroad or receiving blood transfusions. Peripheral blood smear revealed vivax malaria with parasitemia density of 0.53 percent. She demonstrated loss of orientation, especially regarding time and place, and ataxia. Although the initial hydroxychloroquine treatment for malaria was successful, cognitive impairment and ataxia persisted and were not recovered. Brain MRI showed no structural abnormality. Brain PET showed diffuse hypometabolism in right parieto-temporal lobe of the brain.