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 beneficial 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 colonystimulating 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. Many biologic products have improved the outcomes of cancer patients, but the costs can substantially not afford healthcare systems. But also the costs can substantially reduce healthcare systems.Biosimilar products can potentially reduce drug costs and increase patient access to beneficial treatments. AppaloWs a biosimilar product relies on the demonstration of “comparability” or “no clinically meaningful differences ” as compared to its reference biologic product. Ibimilar products for erythropoietin, granulocyte colonystimulating 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. we provide background information about biosimilar products and their regulatory approval processes, followed by a discussion of individual biosimilar drugs.