Our objective was to determine metabolic syndrome (MS) prevalence in Chinese patients with systemic lupus erythematosus (SLE) and to investigate the conditions that contribute to its development. 116 patients with SLE classified according to the American College of Rheumatology (ACR) classification criteria, and 115 controls were enrolled. MS was defined by the joint interim statement of the International Diabetes Federation Task Force on Epidemiology and Prevention; National Heart, Lung, and Blood Institute; American Heart Association; World Heart Federation; International Atherosclerosis Society; and International Association for the Study of Obesity (IDF/NHLBI/AHA/WHF/IAS/IASO). SLE features and treatment of SLE were assessed. Fasting insulin and cortisol levels of 30 newly diagnosed, untreated patients and 33 age and sex-matched controls were detected. MS prevalence was 34.2% in patients with SLE and 14.8% in controls (p=0.002). Lupus patients with MS had less frequency of hydroxychloroquine (HCQ) intake (16.0% vs 45.8%; p=0.012). Untreated patients with SLE had higher levels of fasting insulin (10.92 ± 13.53 vs 5.48 ± 5.43 uU/mL, p<0.001) and plasma cortisol at 16:00 (257.22 ± 177.98 vs 139.84 ± 63.46 nmol/L, p=0.001), but lower plasma cortisol at 08:00 (195.51 ± 149.84 vs 278.95 ± 136.27 nmol/L, p=0.024). Comparisons regarding steroid therapy, levels of insulin and cortisol were not statistically significant between patients with MS and without MS. The Chinese patients with SLE presented a higher MS prevalence and fasting insulin than controls. MS was not associated with the steroid therapy and plasma cortisol. HCQ use proved to be protective against MS. The circadian rhythm of cortisol may differ in patients with SLE.