A polypeptide and polynucleotides encoding same comprising one carboxy-terminal peptide (CTP) of chorionic gonadotrophin attached to an amino terminus of a cytokine and two carboxy-terminal peptides (CTP) of chorionic gonadotrophin attached to a carboxy terminus of a cytokine are disclosed. Pharmaceutical compositions comprising the polypeptide and polynucleotides of the invention and methods of using same are also disclosed.