A biosimilar drug can reference a pioneering drug's clinical and safety package to reduce the burden for regulatory approval. This chapter reviews the patent exclusivities affecting the biosimilar approval process. It presents a brief overview of the regulatory process in Canada, the US, and Europe. This is followed by an analysis of the pertinent patent issues affecting biosimilars. The chapter shows that patent owners and biosimilar manufacturers have to approach patent issues on a region-by-region basis because each jurisdiction differs in the way that patents may be linked, if at all, to the biosimilar regulatory approval process. Biosimilars are regulated in Canada under Health Canada's preexisting powers granted by the Food and Drugs Act and Regulations. The US federal government has created a specially designed, abbreviated biosimilar approval pathway. The Biologics Price Competition and Innovation Act (BPCIA) was part of the Patient Protection and Affordable Care Act. There are no European Community (EC) linkage regulations.