Drugs based on recombinant interferons β are in high demand in clinical practice for first-line therapy of multiple sclerosis. Drugs based on recombinant interferons β-1a and β-1b are registered in the Russian Federation. These proteins have different production technologies and, hence, structures. Recombinant interferon β-1a is a glycosylated protein with a structure close to that of endogenous human interferon. Recombinant interferon β-1b is a non-glycosylated protein that differs by two amino-acid residues from interferon β-1a. These structural features influence the biological properties of drugs based on interferons β-1a and β-1b, in particular, their clinical efficacy, side effects, and induction intensity of neutralizing antibodies. For this reason, a laboratory pharmaceutical examination of the drug quality of interferons β should include confirmation of the specific biological activity and the correspondence of the target protein to the claimed structure. However, domestic and international pharmacopoeial requirements for quality assessment of interferon-β-based drugs are not currently fully adequate. Formulation of unified domestic requirements would allow the registration process to be optimized and provide a basis for harmonization of domestic and international requirements.