BACKGROUND: A class of endogenous single-stranded short noncoding RNAs known as microRNAs (miRNAs) has become important epigenetic regulators of physiological and pathological processes in numerous disorders. They regulate the posttranscriptional expression of many genes to control basic cellular pathways and functions. Many research indicates that miRNAs play a role in the initiation and progression of rheumatoid arthritis (RA). OBJECTIVE: This study was comprehensively focused on the role of miRNA-146a and impaired cellular functions in RA. MATERIALS AND METHODS: A case–control study was conducted on a total of 90 samples, comprising 30 control samples and 60 RA patient samples. Samples of patients were chosen from the Imam Hassan al-Mujtaba Hospital located in Kerbala Governate. RNAClean XP Kit and an RNase-Free DNase Set were used to isolate and purify total RNA. Through statistical analysis, the receiver operating characteristic (ROC) curve was used to determine how effectively the predicted value worked. RESULTS: Patients with RA were shown an increasing level of the folding change of miRNA-146a when compared to the control groups. A comparison of serum level of miRNA-146a fold change in different body mass index (BMI) groups was also performed. The level of folding change was shown a massive increasing that was seen with increasing BMI. It was found that miRNA-146a and folding change were highly significant risk factors in RA. CONCLUSION: MiRNAs-164a may be an appealing alternative for usage as biomarkers in clinical applications such as prognosis and disease detection.