Background: Systemic lupus erythematosus (SLE) is a chronic, multisystem, autoimmune disorder characterised by widespread inflammation of connective tissues affecting the skin, joints, kidneys, heart, lungs, and nervous system. SLE is associated with significant morbidity, thus requiring prompt evaluation, appropriate therapy and long-term follow-up. Objective: This study was performed to measure serum adiponectin in SLE patients and to correlate it with SLEDAI and to evaluate its role as a biomarker of activity in SLE patients specially renal in the hope of preventing or at least postponing renal damage. Patients and methods: This study included 72 subjects, 36 patients and 36 volunteers. The patients were divided into three groups. Group I (active renal) 12 patients having renal disease activity, group II (active non-renal) 12 patients having non-renal disease activity and group III (inactive SLE). 36 apparently healthy volunteers were included (group IV) as a control group. Results: A highly significant difference in serum adiponectin between SLE groups and control group. A highly significant positive correlation between serum adiponectin and 24 h protein in urine. Negative correlation between serum adiponectin and C3 & C4. A significant difference between SLE groups as regards serum anti-double stranded DNA titres, which were higher in renal group patients, also C3 & C4 levels which were lower in the renal group. Serum adiponectin level was not correlated with SLE Disease Activity Index (DAI). Conclusion: Adiponectin level was strongly associated with active SLE with renal disease. Adiponectin level in SLE patients was not correlated with SLEDAI. It may be a promising biomarker for prediction of renal activity of SLE.