With the projected expansion of the biosimilars market, clinicians must assimilate many important issues. These include understanding biosimilar development, building strategies for biosimilar introduction, and developing robust systems for biosimilar pharmacovigilance. With ten tumor necrosis factor inhibitors, a first rituximab biosimilar now on the market, and many more biosimilars currently in development, controversial issues such as multiple biosimilar switching and indication extrapolation also require consideration.