Background and aim: Several lines of evidence exist which suggest that changes in the expression of circulating cytokines are linked to the development or reoccurrence of multiple sclerosis (MS). This project aimed to evaluate the serum levels of relevant cytokines after therapy with IFN-? formulations in MS patients. Material and methods: In this study, blood samples were collected from 70 MS patients undergoing four different types of IFN-? formulation treatment and 100 healthy controls. After 24 months of treatment the serum levels of IL-17A, IL-12 and IFN-g and IL-10 in patients and healthy controls were analyzed by ELISA. Finding: Our results showed that serum levels of IL-17A were significantly higher in patients treated with Cinnovex and Anovex when compared to healthy controls. Serum levels of IL-10 were significantly decreased after therapy with Cinnovex, whereas serum levels of IFN-? were elevated. No difference in serum levels of IL-12 were detected in patients and controls. Conclusion: Results of our study suggest that Cinnovex and Anovex modulate the immune system less than Rebif and Betaferon in MS patients and that an elevated dosage/regime of Cinnovex and Anovex may be required for better regulation of the immune system in MS patients.