In recent years, as more biologic products are going off patent protection, the assessment of biosimilarity for biologic products for regulatory approval has received much attention. The development and evaluation of generic versions of an innovative biologic product has become an important issue for both the pharmaceutical/biotechnology industry and the regulatory agencies. Use of biological agents is increasing, with new indications and increased patient demand. Biosimilar medicines (‘biosimilars’) are biological medicines similar to other, already authorized, biological medicines. Biosimilars are biologic products that are highly similar but not identical to the reference medical products in terms of quality, safety and efficacy. This implies specific research, clinical monitoring, physicians updating of knowledge for a safe and appropriate use of these products. Generic chemical medicines and biosimilars have an important role to play in terms of increasing competition in the marketplace, price reductions for biosimilars are unlikely to be as substantial as those seen for generics. This is because biological medicines, including biosimilars, are more costly to produce and develop than chemical medicines and their generics, and that is why is it important to use statistical methods.