The present invention provides improved processes for purifying liraglutide. Liraglutide is purified via two sequential RP-HPLC purifications followed by a salt-exchange step, where a pH is kept constant in the first and second purification steps. In particular, the processes utilize a halogenated solvent in a sample preparation step, which provides better solubility and an environment suitable for decarboxylation for crude liraglutide prior to a RP-HPLC purification.