Many biologic products have improved the outcomes of cancer patients, but the costs can substantially burden healthcare systems. Biosimilar products can potentially reduce drug costs and increase patient access to beneifcial treatments. Approval of a biosimilar product relies on the demonstration of “comparability” or “no clinically meaningful differences” as compared to its reference biologic product. Biosimilar products for erythropoietin, granulocyte colony-stimulating factor, trastuzumab, and rituximab are already available, and the regulatory processes in various countries are constantly evolving. It is important that oncologists be familiar with the potential issues surrounding the clinical use of biosimilar products. In this review article, we provide background information about biosimilar products and their regulatory approval processes, followed by a discussion of individual biosimilar drugs.