INTRODUCTION AND PURPOSE: Lupus nephritis (LN) is the main cause of morbidity and mortality in systemic lupus erythematosus (SLE) patients, therefore the discovery of new biomarkers, which are reliable for the diagnosis of NL is necessary. Various studies have reported alteration of some miRNAs expression in LN, that considered as biomarkers and/or therapeutic targets in LN. MicroRNA-203 has been associated with the development of nephritis in SLE patients, playing an important role in the initiation and progression of the disease, but research on circulating miRNA-203 expression in LN in clinical practice is still very limited. The aim of this study was to prove the role of microRNA-203 in LN. PATIENTS AND METHODS: Serum was obtained from 40 participants consisting of 20 SLE patients and 20 LN patients. The diagnostic of SLE and LN was based on the ACR 1997 criteria. MicroRNA-203 expression was determined by real-time Polymerase Chain Reaction (PCR). Statistical analysis was performed with Mann-Whitney test. RESULTS: The expression of miRNA-203 in the SLE group was 1.66 (0.00-8.64) and in the NL group was 5.18 (0.25-49.84). There were significant differences in microRNA-203 expression between SLE and LN patients (p=0.003). CONCLUSION: MicroRNA-203 expression might be associated with nephritis manifestations in SLE patients.