The present study was performed to evaluate a set of Micro-RNAs as diagnostic biomarkers of pain intensity in adolescents with chronic fatigue syndrome (CFS) and to correlate with inflammatory markers and pain related comorbidities. Thus, a total of 150 adolescents aged (12-18 years) were invited to participate in this study. They are classified into two groups; adolescents with CFS (n=100) and healthy control (n=50). RT-PCR and immunoassay analysis were used to estimate miRNAs (miR-558, miR-146a, miR-150, miR-124, and miR-143) and immune-inflammatory markers (IL-6, TNF-α, COX-2) respectively.