BACKGROUND: Infection can activate the immune system and may trigger the production of autoantibodies. It has been reported that malaria infection triggers the production of various autoantibodies. Therefore, we investigated the pattern and significance of antinuclear antibodies (ANA) found in patients with malaria infection. METHODS: Our study group included 36 patients who were diagnosed with malaria infection at Mokdong Hospital from July 1998 to July 2001. We performed antinuclear antibody test using indirect immunofluorescence method (Quantafluor, Sanofi Diagnostics Pasteur Inc., USA), extractable nuclear antigen test (ENA) using double immunodiffusion method (Nova Gel, Inova Diagnostics Inc., USA), anti-double stranded DNA Ab test (anti-ds DNA Ab) using Farr assay (DPC anti-DNA, Diagnostic products Corporation, USA), and anti-single stranded DNA Ab test (anti-ssDNA Ab) using enzyme immunoassay method (QUANTA, Lite ssDNA, Inova Diagnostics Inc., USA). RESULTS: Among the 36 patients, 32 patients (88.9%) showed ANA positivity and 27 patients (75.0%) showed cytoskeleton or speckled pattern of ANA. Anti-ssDNA Ab was found in 3 of 20 patients; however, anti-dsDNA Ab and ENA were not found in all patients. Patients who had ANA showed higher levels of IgG, IgM and IgA, compared with those patients who did not have ANA. Follow up (11-37 month) of the 13 patients with ANA positivity revealed no symptoms associated with autoimmune disorder. CONCLUSIONS: Malaria infection may develop ANA, especially cytoskeleton or speckled pattern. The follow up of patients with ANA positivity showed no symptoms associated with any autoimmune disorder, but further evaluation would be necessary to reveal the relationship between malaria infection and development of autoimmune disorder.