Background Middle East Respiratory Syndrome Coronavirus (MERS-CoV) emerged in the Middle East in 2012 and was associated with significant morbidity and mortality. Considering the role of cytokines in MERS-CoV infection and pathogenesis, this study was performed to assess the plasma levels of proinflammatory cytokines among MERS-CoV patients. Methods A total of 46 MERS-CoV infected patients (19 asymptomatic and 27 with symptoms) were compared to 52 normal healthy controls for the levels of proinflammatory cytokines (IL-1β, TNF-α, IL-17, IL-7, IL-6, IFN-α, IL-15) using a customized luminex kit. Results There was no difference observed between asymptomatic MERS-CoV patients and controls, however; the mean plasma levels among MERS-CoV symptomatic patients were significantly higher than asymptomatic MERS-CoV patients and normal controls: IL-1β (16.89 ± 1.23 pg/mL vs 12.80 ± 0.59 pg/mL; p<0.001), TNF-α (14.04 ± 0.93 pg/mL vs 10.35 ± 0.29 pg/mL; p<0.0001), IL-17 (14.33 ± 0.89 pg/mL vs 11.47 ± 0.61 pg/mL; p<0.001), IL-7 (21.56 ± 1.00 pg/mL vs 16.31 ± 0.30 pg/mL; p<0.0001), IL-6 (156.5 ± 37.90 pg/mL vs 18.60 ± 1.59 pg/mL; p<0.0001), and IFN-α (68.73 ± 13.06 pg/mL vs 23.57 ± 1.05 pg/mL; p<0.0001). The mean plasma levels of IL-15 were no different among the groups. Conclusion Significantly elevated proinflammatory cytokines (IL-1β, TNF-α, IL-17, IL-7, IL-6, IFN-α) among symptomatic MERS-CoV infected patients may contribute to manifestations of cytokine storm frequently observed among critically ill MERS-CoV patients.