Background: Insulin sensitivity, blood sugar, lipids, and cardiovascular disease (CVD) are all affected by adiponectin. Adiponectin's involvement in the aetiology of autoimmune illness is still debatable. Objective: To assess the blood level of adiponectin in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), as well as the probable relationship with insulin resistance and disease activity ratings. Patients and methods: A total of 100 SLE, 100 RA, and 100 matched controls were examined. Both the disease activity score (DAS28) and the SLE disease activity index (SLEDAI) were evaluated. Serum adiponectin, C-peptide, and lipid profile were all measured. Both the homeostasis assessment model of insulin resistance (HOMA-IR) and HOMA-B homeostasis model evaluation indices for beta cell function were evaluated. Results: In SLE and RA patients, adiponectin (12.27±1.45, 12.05±0.94 vs 4.12±2.03), C peptide (3.97±2.85, 5.66±3.69 vs 1.8±0.9), fasting insulin levels (37.6±13.2, 35.85±13.68 vs 6.55±2.04), HOMR-IR (7.9±3.03, 7.1±3.09 vs 1.33±0.67) were significantly higher compared to control group (p < 0.001). In patients with SLE and RA, adiponectin had significant positive correlation with ESR and disease activity (p < 0.001, p=0.042 and p < 0.001, p=0.015 respectively) but negative correlation with platelet count (p=0.003, p=0.004), while C-peptide had significant positive correlation with HOMA-B (p= 0.019, 0.041), ESR (p=0.004, p < 0.001), and BMI (p=0.020, p < 0.001) Conclusion: Adiponectin level, C-peptide and indices of IR are elevated in patients with SLE and RA. Adiponectin positively correlated with disease activity and ESR and C-peptide positively correlated with HOMA-B in SLE and RA patients.