Introduction: Biosimilars are biologic medicines that are highly similar to approved biologics, notwithstanding minor differences in clinically inactive components. Since 2007, biosimilars have been approved for use in patients in the European Union (EU) and other regions. European experience provides several lessons as the United States (US) healthcare system prepares for biosimilar approvals. These lessons emphasize the need for adequate efficacy and safety studies, post-marketing surveys and a robust pharmacovigilance system that can accurately track and trace biologics, including biosimilars and their reference products, from the patient to the manufacturer. Areas covered: We review the EU experience with biosimilar pharmacovigilance and discuss the implications for biosimilar pharmacovigilance in the USA. Furthermore, we review several aspects of biosimilar pharmacovigilance, including cohort event monitoring, traceability, biosimilar interchangeability, pharmacovigilance system development, nomenclature and counterfeit tracking. Expert opinion: The availability of biosimilars as lower-cost biologics must carefully consider issues of safety, efficacy and traceability. Stringent pharmacovigilance procedures are required to detect potential differences in safety signals between biosimilars and their reference products. Pharmacovigilance of biologics should include processes that are easily used by prescribing practitioners to ensure that data are consistent and new safety signals are properly reported and assigned to the correct product. © 2013 Informa UK, Ltd.