Aim and Background: For the production of recombinant proteins in eukaryotic cells, especially in the therapeutic field, use of serum free medium instead of medium containing fetal bovine serum is preferred.

Material and methods: protein producing CHO cells were seed into the cell culture media with different levels of FBS and SFM media then cell morphology, viablility and recombinant protein production was assessed.

Results and conclusion: CHO cells showed different morphology in Serum Free media but their protein production and viability did not differ significantly.

Conclusion: The Serum Free media could be used successfully for recombinant protein production by CHO cells instead of serum supplemented media.