Biological products or biopharmaceuticals are medicinal products derived from living systems and manufactured by modern biotechnological methods that differ widely from the traditional synthetic drugs. Monoclonal antibodies are the most rapidly growing type of biologic. They are much larger and more complex molecules with inherent diversity; therefore, different manufacturers cannot produce identical biological products, even with the same type of host expression system and equivalent technologies. Thus, legal follow-on biologics manufactured and marketed after patent expiration are usually referred to as biosimilars. Biosimilarity is based on a comparability exercise whereby unavoidable clinical differences are evaluated and must meet equivalence or non-inferiority criteria. Biosimilars need to comply with different regulatory requirements for market authorization in different sites. There are several other related issues that need to be defined by the national authorities, such as interchangeability, labeling and prescribing information. The Brazilian health surveillance agency follows the key principles established by the World Health Organization for the assessment of biosimilarity, although does not adopt the name 'biosimilar'. However, the agency also made a compromise on a standalone application pathway that does not require the usual comparability exercise with the reference product, originating nonbiosimilar copies. Interchangeability and the use of nonproprietary names are not regulated, giving rise to pressures on physicians and conflicts of interest in the decision making on biosimilar use. The scope of this article is to present the Brazilian regulation on biosimilars, its strengths and weaknesses, and to discuss it in the face of regulations in the USA and Europe.