Background: Several investigations have found a correlation between serum anti-C1q autoantibodies and peripheral lymphocyte apoptosis among systemic lupus erythematosus (SLE) patients. Objective: It was to assess correlation between anti-C1q, lupus nephritis and other markers of lupus activity. Patients and Methods: This case-control study was conducted in Internal Medicine Department in cooperation with Clinical Pathology Department. This study was performed on 72 cases and were allocated into three equal groups: SLE with nephritis group, SLE without nephritis group, and control group. Measurements of anti-C1q titers were carried out with by (ELISA) kits. Results: Anti-C1q antibody levels varied significantly amongst the groups. Post hoc test showed that there was a statistical significance increase in anti-C1q among SLE with nephritis compared to SLE who don’t have nephritis and control and among SLE without nephritis compared to control. Anti-C1q antibodies validity to diagnose LN among the studied group showed that anti-C1q at cut off >88.058 ng/ml had sensitivity 75%, specificity 75%, accuracy 75%, PPV of 75% and NPV of 75% in diagnosis of LN among cases groups. Conclusion: Anti-Clq autoantibodies, like other standard markers like renal SLEDAI, correlate with renal flare-ups as well as renal disease activity.