Aim of the work: To investigate whether serum leptin levels are elevated in patients with rheumatoid arthritis (RA) and whether these levels correlate with disease activity. Patients and methods: A case- control study was made on 37 patients with RA and 34 healthy control subjects. The following values were assessed for each patient: erythrocyte sedimentation rate (ESR), C reactive protein (CRP), rheumatoid factor (RF), swollen and tender joint counts, disease activity score 28 (DAS28), health assessment questionnaire score (HAQ), visual analog scale (VAS) of pain and serum leptin concentrations. Results: Patients with RA had mild to moderate (DAS28 < 5.1) disease activity. The mean serum leptin in patients with RA (12.15 +/- 11.48 ng/mL) was significantly higher (p< 0.001) than controls (3.99 +/- 1.84 ng/ mL). Serum leptin levels were significantly (p< 0.001) higher in female RA patients than in female controls. A nonsignificant difference (p = 0.41) was found between male patients with RA and male controls. Serum leptin levels were significantly (p< 0.001) higher in women than in men in both patients and controls. Serum leptin levels did not show correlation with age, disease duration, duration of morning stiffness, VAS, number of swollen and tender joints, DAS28, HAQ, ESR or CRP in patients with RA. Serum leptin levels were correlated positively with BMI in RA patients. The BMI was significantly higher (p < 0.001) in female than in male patients with RA. Conclusion: Although leptin levels were higher in RA patients, there was no correlation with disease activity parameters, therefore, leptin levels cannot be used to reflect disease activity. (C) 2012 Egyptian Society for Joint Diseases and Arthritis. Production and hosting by Elsevier B.V. Open access under CC BY-NC-ND license.