It is estimated that at least 30 to 40% of asthma attacks in adults are related to respiratory infections with viruses. The majority of asthma-related viruses include respiratory syncytial virus (RSV), rhinovirus, and parainfluenza. Inflammatory cytokines are supposed to play a vital role in causing inflammation of the respiratory tract as regulators of proliferation, chemotaxis, and activation of inflammatory cells. The aim of this study is to assess the role of Granulocyte Macrophage-Colony Stimulating Factor (GMCSF) in asthmatic airway hyper-responsiveness associated with RSV infections. Forty five asthmatic cases and 45 healthy individuals were studied in a cross-sectional design. All asthmatics underwent symptom score assessment.GMCSF concentrations in sputum and RSV-IgM/IgG in serum samples were measured for all participants by Enzyme Linked Immuno-Sorbent Assay (ELISA). The GM-CSF concentration level was significantly higher in asthmatics (270.27± 194.87pg/mL) especially among moderate and severe disease with mean concentration of 197.33±98.47 and 521.08± 310.04 respectively, compared to healthy controls (22.20±21.27 pg/ mL) (p =0.0001). The sputum level of GM-CSF in asthmatics is highly significant associated with positive anti-RSV IgG sera which represents 35/45(77.8%) with mean GM-CSF concentration of (276.99± 86.42) compared with controls at about 31/45 (68.9%) with GM-CSF mean concentration of (22.84±23.47). On the other hand, positive anti-RSV IgM in asthma cases was 8 out of 45(17.8 %) with GM-CSF mean concentration of (307.25± 306.65). Furthermore, GM-CSF sputum level was significantly correlated with eosinophil count especially in moderate and severe asthma. This study revealed that GM-CSF level is associated with eosinophilia and indicates asthma severity that might be evident during RSV infection .The distinctive GM-CSF features observed in the sputum from asthmatics with RSV may be useful as a diagnostic methods to help match patients with antibody therapy.