Background: Juvenile idiopathic arthritis (JIA) is a term that encompasses all forms of arthritis that begin before a patient is aged 16 years that persist for more than 6 weeks and are of unknown origin. It is the most common childhood chronic rheumatic disease and causes much disability. We investigated the relation of serum 14-3-3 η (eta) protein in oligoarticular JIA (OJIA) and; the disease activity and severity. Methods: This study is a case control study including 14 JIA patients and 14 control group. Patients were (6 males and 8 females).14-3-3η was measured for all patients and control volunteers by enzyme-linked immunosorbent assay (ELISA) technique. ANA was measured by indirect immunofluorescence (IIF) technique. Disease activity was assessed by the Juvenile Arthritis Disease Activity Score27 (JADAS-27). Functional ability was assessed by childhood health assessment questionnaire (CHAQ), and disease severity was assessed by juvenile arthritis damage index (JADI). Radiological damage was assessed by Poznanski score. Results: Elevated 14-3-3 η levels were detected in 5/14 (35.7%) patients. Positivity for 14- 3-3 η was significantly related to disease activity, severity and ANA. Positivity for 14-3-3 η had no significant correlation with CHAQ or Posnanski score. Conclusion: Serum 14-3-3 η can be detected in oligoarticular JIA patients, and appears to correlate with disease activity, severity and (ANA). But no correlation with CHAQ or Poznanski score.